Bio


Dauskardt and his group have worked extensively on integrating new materials into emerging technologies including thin-film structures for nanoscience and energy technologies, high-performance composite and laminates for aerospace, and on biomaterials and soft tissues in bioengineering. His group has pioneered methods for characterizing adhesion and cohesion of thin films used extensively in device technologies. His research on wound healing has concentrated on establishing a biomechanics framework to quantify the mechanical stresses and biologic responses in healing wounds and define how the mechanical environment affects scar formation. Experimental studies are complimented with a range of multiscale computational capabilities. His research includes interaction with researchers nationally and internationally in academia, industry, and clinical practice.

Honors & Awards


  • Visiting Professor, Nanyang Technological Universit (2016)
  • Ruth G. and William K. Bowes Professor, Stanford University (2013)
  • Henry Maso Award, The International Federation of Societies of Cosmetic Chemists (2011)
  • Shared University Research Award, IBM (2011)
  • Elected Fellow, ASM International (2010)
  • Structural Materials Distinguished Scientist/Engineer Award, The Metallurgical Society (2010)
  • University Researcher Award, Semiconductor Industry Association (2010)
  • Elected Fellow, American Ceramics Society (2008)
  • Multilevel Interconnection (VMIC) International Conference Award, VLSI/ULSI (2008)
  • Thin Film User Group Special Award, American Vacuum Society (2008)
  • Distinguished Speaker, Department of Materials Science and Engineering, Penn State (2006)
  • Faculty Award, IBM (2006)
  • International Silver Medal, ASM (2003)
  • Alexander von Humboldt Research Award, Alexander von Humboldt Foundation (2002)
  • Dana Adams Griffin Award, Stanford University (1994)
  • Outstanding Scientific Accomplishment Award in Ceramics and Metallurgy, U.S. Department of Energy (1989)

Professional Education


  • PhD, UC Berkeley/Witwatersrand (1988)

2023-24 Courses


Stanford Advisees


All Publications


  • Indirect Liftoff Mechanism for High-Throughput, Single-Source Laser Scribing for Perovskite Solar Modules ADVANCED ENERGY MATERIALS Flick, A. C., Rolston, N., Dauskardt, R. H. 2024
  • Predicting encapsulant delamination in photovoltaic modules bridging photochemical reaction kinetics and fracture mechanics PROGRESS IN PHOTOVOLTAICS Liu, K., Thornton, P., D'hooge, D. R., Dauskardt, R. H. 2023

    View details for DOI 10.1002/pip.3771

    View details for Web of Science ID 001131535500001

  • Water vapor transmission rate measurement for moisture barriers using infrared imaging MATERIALS CHEMISTRY AND PHYSICS Pan, Z., Bora, M., Gee, R., Dauskardt, R. H. 2023; 308
  • Carbon dioxide foam bubbles enhance skin penetration through the stratum corneum layer with mechanical mechanism. Colloids and surfaces. B, Biointerfaces Berkey, C. A., Styke, C., Yoshitake, H., Sonoki, Y., Uchiyama, M., Dauskardt, R. H. 2023; 231: 113538

    Abstract

    Topical skin formulations often include penetration enhancers that interact with the outer stratum corneum (SC) layer to chemically enhance diffusion. Alternatively, penetration can be mechanically enhanced with simple rubbing in the presence of solid particles sometimes included to exfoliate the top layers of the SC. Our goal was to evaluate micron-sized carbon dioxide bubbles included in a foamed moisturizing formulation as a mechanical penetration enhancement strategy. We show that moisturizing foam bubbles cause an increase in SC formulation penetration using both mechanical and spectroscopic characterization. Our results suggest viscous liquid film drainage between coalescing gaseous bubbles creates local regions of increased hydrodynamic pressure in the foam liquid layer adjacent to the SC surface that enhances treatment penetration. An SC molecular diffusion model is used to rationalize the observed behavior. The findings indicate marked increased levels of treatment concentration in the SC at 2h and that persists to 18h after exposure, far exceeding non-foamed treatments. The study suggests an alternate strategy for increasing formulation penetration with a non-chemical mechanism.

    View details for DOI 10.1016/j.colsurfb.2023.113538

    View details for PubMedID 37738871

  • Sensory neuron activation from topical treatments modulates the sensorial perception of human skin. PNAS nexus Bennett-Kennett, R., Pace, J., Lynch, B., Domanov, Y., Luengo, G. S., Potter, A., Dauskardt, R. H. 2023; 2 (9): pgad292

    Abstract

    Neural signaling of skin sensory perception from topical treatments is often reported in subjective terms such as a sensation of skin "tightness" after using a cleanser or "softness" after applying a moisturizer. However, the mechanism whereby cutaneous mechanoreceptors and corresponding sensory neurons are activated giving rise to these perceptions has not been established. Here, we provide a quantitative approach that couples in vitro biomechanical testing and detailed computational neural stimulation modeling along with a comprehensive in vivo self-assessment survey to demonstrate how cutaneous biomechanical changes in response to treatments are involved in the sensorial perception of the human skin. Strong correlations are identified between reported perception up to 12 hours post treatment and changes in the computed neural stimulation from mechanoreceptors residing deep under the skin surface. The study reveals a quantitative framework for understanding the biomechanical neural activation mechanism and the subjective perception by individuals.

    View details for DOI 10.1093/pnasnexus/pgad292

    View details for PubMedID 37771342

    View details for PubMedCentralID PMC10531117

  • Environment assisted cyclic fatigue crack growth testing of polymer/ inorganic laminates under strain energy release rate control INTERNATIONAL JOURNAL OF FATIGUE Riedl, G., Wallner, G. M., Pugstaller, R., Dauskardt, R. H. 2023; 173
  • An open-source environmental chamber for materials-stability testing using an optical proxy DIGITAL DISCOVERY Keesey, R., Tiihonen, A., Siemenn, A. E., Colburn, T. W., Sun, S., Hartono, N., Serdy, J., Zeile, M., He, K., Gurtner, C. A., Flick, A. C., Batali, C., Encinas, A., Naik, R. R., Liu, Z., Oviedo, F., Peters, I., Thapa, J., Parker Tian, S., Dauskardt, R. H., Norquist, A. J., Buonassisi, T. 2023; 2 (2): 422-440

    View details for DOI 10.1039/d2dd00089j

    View details for Web of Science ID 001101481100001

  • Linking Interfacial Bonding and Thermal Conductivity in Molecularly-Confined Polymer-Glass Nanocomposites with Ultra-High Interfacial Density. Small (Weinheim an der Bergstrasse, Germany) Wang, Y., Collinson, D. W., Kwon, H., Miller, R. D., Lionti, K., Goodson, K. E., Dauskardt, R. H. 2023: e2301383

    Abstract

    Thermal transport in polymer nanocomposites becomes dependent on the interfacial thermal conductance due to the ultra-high density of the internal interfaces when the polymer and filler domains are intimately mixed at the nanoscale. However, there is a lack of experimental measurements that can link the thermal conductance across the interfaces to the chemistry and bonding between the polymer molecules and the glass surface. Characterizing the thermal properties of amorphous composites are a particular challenge as their low intrinsic thermal conductivity leads to poor measurement sensitivity of the interfacial thermal conductance. To address this issue here, polymers are confined in porous organosilicates with high interfacial densities, stable composite structure, and varying surface chemistries. The thermal conductivities and fracture energies of the composites are measured with frequency dependent time-domain thermoreflectance (TDTR) and thin-film fracture testing, respectively. Effective medium theory (EMT) along with finite element analysis (FEA) is then used to uniquely extract the thermal boundary conductance (TBC) from the measured thermal conductivity of the composites. Changes in TBC are then linked to the hydrogen bonding between the polymer and organosilicate as quantified by Fourier-transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. This platform for analysis is a new paradigm in the experimental investigation of heat flow across constituent domains.

    View details for DOI 10.1002/smll.202301383

    View details for PubMedID 36971287

  • Technology Roadmap for Flexible Sensors. ACS nano Luo, Y., Abidian, M. R., Ahn, J. H., Akinwande, D., Andrews, A. M., Antonietti, M., Bao, Z., Berggren, M., Berkey, C. A., Bettinger, C. J., Chen, J., Chen, P., Cheng, W., Cheng, X., Choi, S. J., Chortos, A., Dagdeviren, C., Dauskardt, R. H., Di, C. A., Dickey, M. D., Duan, X., Facchetti, A., Fan, Z., Fang, Y., Feng, J., Feng, X., Gao, H., Gao, W., Gong, X., Guo, C. F., Guo, X., Hartel, M. C., He, Z., Ho, J. S., Hu, Y., Huang, Q., Huang, Y., Huo, F., Hussain, M. M., Javey, A., Jeong, U., Jiang, C., Jiang, X., Kang, J., Karnaushenko, D., Khademhosseini, A., Kim, D. H., Kim, I. D., Kireev, D., Kong, L., Lee, C., Lee, N. E., Lee, P. S., Lee, T. W., Li, F., Li, J., Liang, C., Lim, C. T., Lin, Y., Lipomi, D. J., Liu, J., Liu, K., Liu, N., Liu, R., Liu, Y., Liu, Y., Liu, Z., Liu, Z., Loh, X. J., Lu, N., Lv, Z., Magdassi, S., Malliaras, G. G., Matsuhisa, N., Nathan, A., Niu, S., Pan, J., Pang, C., Pei, Q., Peng, H., Qi, D., Ren, H., Rogers, J. A., Rowe, A., Schmidt, O. G., Sekitani, T., Seo, D. G., Shen, G., Sheng, X., Shi, Q., Someya, T., Song, Y., Stavrinidou, E., Su, M., Sun, X., Takei, K., Tao, X. M., Tee, B. C., Thean, A. V., Trung, T. Q., Wan, C., Wang, H., Wang, J., Wang, M., Wang, S., Wang, T., Wang, Z. L., Weiss, P. S., Wen, H., Xu, S., Xu, T., Yan, H., Yan, X., Yang, H., Yang, L., Yang, S., Yin, L., Yu, C., Yu, G., Yu, J., Yu, S. H., Yu, X., Zamburg, E., Zhang, H., Zhang, X., Zhang, X., Zhang, X., Zhang, Y., Zhang, Y., Zhao, S., Zhao, X., Zheng, Y., Zheng, Y. Q., Zheng, Z., Zhou, T., Zhu, B., Zhu, M., Zhu, R., Zhu, Y., Zhu, Y., Zou, G., Chen, X. 2023

    Abstract

    Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.

    View details for DOI 10.1021/acsnano.2c12606

    View details for PubMedID 36892156

  • Methodology for local ageing and damage development characterization of solar glass/encapsulant interfaces under superimposed fatigue stresses and environmental influences SOLAR ENERGY MATERIALS AND SOLAR CELLS Riedl, G., Wallner, G. M., Pugstaller, R., Saeckl, G., Dauskardt, R. H. 2022; 248
  • Gas cluster etching for the universal preparation of polymer composites for nano chemical and mechanical analysis with AFM APPLIED SURFACE SCIENCE Collinson, D. W., Nepal, D., Zwick, J., Dauskardt, R. H. 2022; 599
  • Dependence of adhesion on degradation mechanisms of ethylene co-vinyl acetate encapsulants over the lifetime of photovoltaic modules SOLAR ENERGY MATERIALS AND SOLAR CELLS Thornton, P., Moffitt, S. L., Schelhas, L. T., Dauskardt, R. H. 2022; 244
  • The Natural and Accelerated Evolution of EVA Adhesion Through Intermediate Exposures IEEE JOURNAL OF PHOTOVOLTAICS Thornton, P., Bosco, N., Dauskardt, R. H. 2022
  • From decoding the perception of tightness to a clinical proof of soothing effects derived from natural ingredients in a moisturizer. International journal of cosmetic science Hendrickx-Rodriguez, S., Connetable, S., Lynch, B., Pace, J., Bennett-Kennett, R., Luengo, G. S., Dauskardt, R., Potter, A. 2022

    Abstract

    OBJECTIVE: To decode the feeling of skin tightness after application of a cosmetic product and how to soothe this discomfort. To pursue this aim, we considered the ingredient's effect on stratum corneum (SC) biomechanics to differentiate between consumers prone to tightness from those that are not and correlate these effects with mechanoreceptor activation.METHODS: In vivo clinical trials were used to assess the tightness perception dichotomy between groups of Caucasian women; in vitro experiments were used to measure the mechanical stresses induced in the SC after cleanser and moisturizer application; and in silico simulations were used to illustrate how the measured mechanical stresses in the SC result in the development of strains at the depth of cutaneous mechanoreceptors, triggering tightness perceptual responses.RESULTS: Before any cream application, women prone to tightness tend to have a more rigid SC than their less sensitive counterparts, however cleanser application increases SC stiffness in all women. Surprisingly, no correlation was found between tightness perception and hydration measurements by the Corneometer or barrier function, as evaluated by transepidermal water loss (TEWL). Self-declared tightness and dryness scores were strongly associated with a self-described sensitive skin. After application of the optimized moisturizing formula, Osmoskin containing natural waxes with good filming properties, consumers report a strong decrease in tightness and dryness perception. These results match with laboratory experiments where the cleanser was shown to increase SC drying stresses by 34%, while subsequent application of Osmoskin decreased stresses by 48%. Finite element modeling (FEM), using experimental results as input, elucidates the differences in perception between the two groups of women. It makes clear that Osmoskin changes the mechanical status of the stratum corneum, producing strains in underlying epidermis that activates multiple cutaneous mechano-receptors at a level correlated with the self-perceived comfort.CONCLUSION: Integration of the in vivo, in vitro, and in silico approaches provides a novel framework for fully understanding how skin tightness sensations form and propagate, and how these sensations can be alleviated through the design of an optimized moisturizer.

    View details for DOI 10.1111/ics.12797

    View details for PubMedID 35775314

  • Polyimide Hybrid Nanocomposites with Controlled Polymer Filling and Polymer-Matrix Interaction. ACS applied materials & interfaces Wang, C., Kilic, K. I., Koerner, H., Baur, J. W., Varshney, V., Lionti, K., Dauskardt, R. H. 2022

    Abstract

    Polyimide hybrid nanocomposites with the polyimide confined at molecular length scales exhibit enhanced fracture resistance with excellent thermal-oxidative stability at low density. Previously, polyimide nanocomposites were fabricated by infiltration of a polyimide precursor into a nanoporous matrix followed by sequential thermally induced imidization and cross-linking of the polyimide under nanometer-scale confinement. However, byproducts formed during imidization became volatile at the cross-linking temperature, limiting the polymer fill level and degrading the nanocomposite fracture resistance. This is solved in the present work with an easier approach where the nanoporous matrix is filled with shorter preimidized polyimide chains that are cross-linked while in the pores to eliminate the need for confined imidization reactions, which produces better results compared to the previous study. In addition, we selected a preimidized polyimide that has a higher chain mobility and a stronger interaction with the matrix pore surface. Consequently, the toughness achieved with un-cross-linked preimidized polyimide chains in this work is equivalent to that achieved with the cross-linking of the previously used polyimide chains and is doubled when preimidized polyimide chains are cross-linked. The increased chain mobility enables more efficient polymer filling and higher polymer fill levels. The higher polymer-pore surface interaction increases the energy dissipation during polyimide molecular bridging, increasing the nanocomposite fracture resistance. The combination of the higher polymer fill and the stronger polymer-surface interaction is shown to provide significant improvements to the nanocomposite fracture resistance and is validated with a molecular bridging model.

    View details for DOI 10.1021/acsami.2c02575

    View details for PubMedID 35679607

  • Insights into the Mechanical Properties of Ultrathin Perfluoropolyether-Silane Coatings. Langmuir : the ACS journal of surfaces and colloids Zhao, O., Collinson, D. W., Ohshita, S., Naito, M., Nakano, N., Tortissier, G., Nomura, T., Dauskardt, R. H. 2022

    Abstract

    Ultrathin perfluoropolyether-silane (PFPE-silane) films offer excellent functionality as antifingerprint coatings for display touchscreens due to their oleophobic, hydrophobic, and good adhesion properties. During smartphone use, PFPE-silane coatings undergo many abrasion cycles which limit the coating lifetime, so a better understanding of how to optimize the film structure for improved mechanical durability is desired. However, the hydrophobic and ultrathin (1-10 nm) nature of PFPE-silane films renders them very difficult to experimentally characterize. In this study, the cohesive fracture energy and elastic modulus, which are directly correlated with hardness and better wear resistance of 3.5 nm-thick PFPE-silane films were, respectively, measured by double cantilever beam testing and atomic force microscopy indentation. Both the cohesive fracture energy and modulus are shown to be highly dependent on the underlying film structure. Both values increase with optimal substrate conditions and a higher number of silane groups in the PFPE-silane precursor. The higher cohesive fracture energy and modulus values are suggested to be the result of the changes in the film chemistry and structure, leading to higher cross-linking density. Therefore, future work on optimizing PFPE-silane film wear resistance should focus on pathways to improve the cross-linking density. Subcritical fracture testing in humid environments reveals that humidity negatively affects the fracture properties of PFPE-silane films.

    View details for DOI 10.1021/acs.langmuir.2c00625

    View details for PubMedID 35543410

  • Machine learning with knowledge constraints for process optimization of open-air perovskite solar cell manufacturing JOULE Liu, Z., Rolston, N., Flick, A. C., Colburn, T. W., Ren, Z., Dauskardt, R. H., Buonassisi, T. 2022; 6 (4): 834-849
  • Topological supramolecular network enabled high-conductivity, stretchable organic bioelectronics. Science (New York, N.Y.) Jiang, Y., Zhang, Z., Wang, Y. X., Li, D., Coen, C. T., Hwaun, E., Chen, G., Wu, H. C., Zhong, D., Niu, S., Wang, W., Saberi, A., Lai, J. C., Wu, Y., Wang, Y., Trotsyuk, A. A., Loh, K. Y., Shih, C. C., Xu, W., Liang, K., Zhang, K., Bai, Y., Gurusankar, G., Hu, W., Jia, W., Cheng, Z., Dauskardt, R. H., Gurtner, G. C., Tok, J. B., Deisseroth, K., Soltesz, I., Bao, Z. 2022; 375 (6587): 1411-1417

    Abstract

    Intrinsically stretchable bioelectronic devices based on soft and conducting organic materials have been regarded as the ideal interface for seamless and biocompatible integration with the human body. A remaining challenge is to combine high mechanical robustness with good electrical conduction, especially when patterned at small feature sizes. We develop a molecular engineering strategy based on a topological supramolecular network, which allows for the decoupling of competing effects from multiple molecular building blocks to meet complex requirements. We obtained simultaneously high conductivity and crack-onset strain in a physiological environment, with direct photopatternability down to the cellular scale. We further collected stable electromyography signals on soft and malleable octopus and performed localized neuromodulation down to single-nucleus precision for controlling organ-specific activities through the delicate brainstem.

    View details for DOI 10.1126/science.abj7564

    View details for PubMedID 35324282

  • High-brightness all-polymer stretchable LED with charge-trapping dilution. Nature Zhang, Z., Wang, W., Jiang, Y., Wang, Y., Wu, Y., Lai, J., Niu, S., Xu, C., Shih, C., Wang, C., Yan, H., Galuska, L., Prine, N., Wu, H., Zhong, D., Chen, G., Matsuhisa, N., Zheng, Y., Yu, Z., Wang, Y., Dauskardt, R., Gu, X., Tok, J. B., Bao, Z. 2022; 603 (7902): 624-630

    Abstract

    Next-generation light-emitting displays on skin should be soft, stretchable and bright1-7. Previously reported stretchable light-emitting devices were mostly basedon inorganic nanomaterials, such as light-emitting capacitors, quantum dots or perovskites6-11. They either require high operating voltage or have limited stretchability and brightness, resolution or robustness under strain. On the other hand, intrinsically stretchable polymer materials hold the promise of good strain tolerance12,13. However, realizing high brightness remains a grand challenge for intrinsically stretchable light-emitting diodes. Here we report a material design strategy and fabrication processes to achieve stretchable all-polymer-based light-emitting diodes with high brightness (about 7,450candela per square metre), current efficiency (about 5.3candela per ampere) and stretchability (about 100per cent strain). We fabricate stretchable all-polymer light-emitting diodes coloured red, green and blue, achieving both on-skin wireless powering and real-time displaying of pulse signals. This work signifies a considerable advancement towards high-performance stretchable displays.

    View details for DOI 10.1038/s41586-022-04400-1

    View details for PubMedID 35322250

  • Biomechanical Analysis of the Ross Procedure in an Ex Vivo Left Heart Simulator. World journal for pediatric & congenital heart surgery Bryan, A. Y., Brandon Strong, E., Kidambi, S., Gilligan-Steinberg, S., Bennett-Kennett, R., Lee, J. Y., Imbrie-Moore, A., Moye, S. C., Hendrickx-Rodriguez, S., Wang, H., Dauskardt, R. H., Joseph Woo, Y., Ma, M. R. 2022; 13 (2): 166-174

    Abstract

    BACKGROUND: Neo-aortic pulmonary autografts often experience root dilation and valve regurgitation over time. This study seeks to understand the biomechanical differences between aortic and neo-aortic pulmonary roots using a heart simulator.METHODS: Porcine aortic, neo-aortic pulmonary, and pulmonary roots (n=6) were mounted in a heart simulator (parameters: 100 mm Hg, 37 °C, 70 cycles per minute, 5.0 L/min cardiac output). Echocardiography was used to study root distensibility (percentage change in luminal diameter between systole and diastole) and valve function. Leaflet motion was tracked with high-speed videography. After 30 min in the simulator, leaflet thickness (via cryosectioning), and multiaxial modulus (via lenticular hydrostatic deformation testing) were obtained.RESULTS: There were no significant differences between aortic and neo-aortic pulmonary leaflet motion, including mean opening velocity (218 vs 248 mm/s, P=.27) or mean closing velocity (116 vs 157 mm/s, P=.12). Distensibility was similar between aortic (8.5%, 1.56 mm) and neo-aortic pulmonary (7.8%, 1.12 mm) roots (P=.59). Compared to virgin controls, native pulmonic roots exposed to systemic pressure for 30 min had reduced leaflet thickness (630 vs 385 m, P=.049) and a reduced Young's modulus (3,125 vs 1,089 kPa, P=.077). In contrast, the aortic roots exposed to pressure displayed no significant difference in aortic leaflet thickness (1,317 vs 1,256 m, P=.27) or modulus (5,931 vs 3,631 kPa, P=.56).CONCLUSIONS: Neo-aortic pulmonary roots demonstrated equivalence in valve function and distensibility but did experience changes in biomechanical properties and morphology. These changes may contribute to long-term complications associated with the Ross procedure.

    View details for DOI 10.1177/21501351211070288

    View details for PubMedID 35238706

  • Ectoine disperses keratin and alters hydration kinetics in stratum corneum. Biochemistry and biophysics reports Bow, J. R., Sonoki, Y., Uchiyama, M., Dauskardt, R. H. 2021; 28: 101134

    Abstract

    Moisturizing compounds are commonly applied topically to human stratum corneum (SC). Many types of molecular species are employed, most commonly including humectants and occlusives. We find new evidence of keratin dispersion caused by the moisturizing compound ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid), and provide the first characterization of its impacts on the hydration kinetics and biomechanics of SC. A second compound, 2-(2-hydroxyethoxy)ethylguanidine succinate (HEG) was investigated for comparison. A suite of biomechanical and biochemical assays including FTIR, drying stress, and cellular cohesion were used. Studies were conducted on normal, lipid-extracted, and lipid plus natural moisturizing factor extracted SC. Ectoine was found to improve the dispersity and hydration of keratin bundles in corneocytes. It also decreased rates of stress development in lipid extracted SC when exposed to a dry environment by 30% while improving stress reduction during rehydration by 20%. Peak stresses were increased in harsh drying environments of <5% RH, but SC swelling measurements suggest that water retention was improved in ambient conditions. Further, changes up to 4J/m2 were seen in cohesion after ectoine treatments, suggesting corneodesmosome interactions. HEG was tested and found to disperse keratin without impacting corneodesmosomes. These results indicate that keratin dispersants produce beneficial effects on SC hydration kinetics, ultimately resulting in higher SC hydration under ambient conditions.

    View details for DOI 10.1016/j.bbrep.2021.101134

    View details for PubMedID 34584987

  • Robust, High-Performing Maize-Perovskite-Based Solar Cells with Improved Stability. ACS applied energy materials Giuri, A., Rolston, N., Colella, S., Listorti, A., Esposito Corcione, C., Elmaraghi, H., Lauciello, S., Dauskardt, R. H., Rizzo, A. 2021; 4 (10): 11194-11203

    Abstract

    Herein, we focus on improving the long-term chemical and thermomechanical stability of perovskite solar cells (PSCs), two major challenges currently limiting their commercial deployment. Our strategy incorporates a long-chain starch polymer into the perovskite precursor. The starch polymer confers multiple beneficial effects by forming hydrogen bonds with the methylammonium iodide precursor, templating perovskite growth that results in a compact and homogeneous film deposited in a simple one-step coating (antisolvent-free). The inclusion of starch in the methylammonium lead iodide films strongly improves their thermomechanical and environmental stability while maintaining a high photovoltaic performance. The fracture energy (G c) of the film is increased to above 5 J/m2 by creating a nanocomposite that provides intrinsic reinforcement at grain boundaries. Additionally, improved optoelectronic properties achieved with the starch polymer enable good photostability of the active layer and enhanced resistance to thermal cycling.

    View details for DOI 10.1021/acsaem.1c02058

    View details for PubMedID 35928767

    View details for PubMedCentralID PMC9342243

  • Robust, High-Performing Maize-Perovskite-Based Solar Cells with Improved Stability ACS APPLIED ENERGY MATERIALS Giuri, A., Rolston, N., Colella, S., Listorti, A., Corcione, C., Elmaraghi, H., Lauciello, S., Dauskardt, R. H., Rizzo, A. 2021; 4 (10): 11194-11203
  • Low-temperature sprayed SnOx nanocomposite films with enhanced hole blocking for efficient large area perovskite solar cells JOURNAL OF MATERIALS CHEMISTRY A Zhang, J., Ding, Y., Jiang, G., Flick, A. C., Pan, Z., Scheideler, W. J., Zhao, O., Chen, J. P., Yang, L., Rolston, N., Dauskardt, R. H. 2021

    View details for DOI 10.1039/d1ta05969f

    View details for Web of Science ID 000693681000001

  • Low temperature open-air plasma deposition of amorphous tin oxide for perovskite solar cells THIN SOLID FILMS Zhao, O., Ding, Y., Cheng, D., Zhang, J., Hilt, F., Rolston, N., Jiang, G., Dauskardt, R. H. 2021; 730
  • Predicting hydration and moisturizer ingredient effects on mechanical behavior of human stratum corneum EXTREME MECHANICS LETTERS Berkey, C., Biniek, K., Dauskardt, R. H. 2021; 46
  • Computational prediction of the molecular configuration of three-dimensional network polymers. Nature materials De Keer, L., Kilic, K. I., Van Steenberge, P. H., Daelemans, L., Kodura, D., Frisch, H., De Clerck, K., Reyniers, M., Barner-Kowollik, C., Dauskardt, R. H., D'hooge, D. R. 2021

    Abstract

    The three-dimensional arrangement of natural and synthetic network materials determines their application range. Control over the real-time incorporation of each building block and functional group is desired to regulate the macroscopic properties of the material from the molecular level onwards. Here we report an approach combining kinetic Monte Carlo and molecular dynamics simulations that chemically and physically predicts the interactions between building blocks in time and in space for the entire formation process of three-dimensional networks. This framework takes into account variations in inter- and intramolecular chemical reactivity, diffusivity, segmental compositions, branch/network point locations and defects. From the kinetic and three-dimensional structural information gathered, we construct structure-property relationships based on molecular descriptors such as pore size or dangling chain distribution and differentiate ideal from non-ideal structural elements. We validate such relationships by synthesizing organosilica, epoxy-amine and Diels-Alder networks with tailored properties and functions, further demonstrating the broad applicability of the platform.

    View details for DOI 10.1038/s41563-021-01040-0

    View details for PubMedID 34183809

  • Perspectives of Open-Air Processing to Enable Perovskite Solar Cell Manufacturing FRONTIERS IN ENERGY RESEARCH Rolston, N., Sleugh, A., Chen, J. P., Zhao, O., Colburn, T. W., Flick, A. C., Dauskardt, R. H. 2021; 9
  • Comprehensive characterization of the structure and properties of human stratum corneum relating to barrier function and skin hydration: modulation by a moisturizer formulation. Experimental dermatology Galliano, M., Tfayli, A., Dauskardt, R. H., Payre, B., Carrasco, C., Bessou-Touya, S., Baillet-Guffroy, A., Duplan, H. 2021

    Abstract

    The stratum corneum (SC) is key in the maintenance of the biomechanical barrier and hydration of skin. Our previous investigations showed beneficial effects of a combination of emollients on water capture and retention and protein and lipid organization, all of which are linked to dryness and dry skin damage. Here, we show how a formulation containing an emollient combination ("Trio") and its basal formulation (placebo) impacted the descriptors of SC hydration in SC layers. Only the Trio formulation-not its placebo formulation-modified SC biomechanical drying stress behaviour and imparted a high capacity to protect it from dehydration. This was in accordance with findings at the molecular level using Raman analyses and at the structural level using cryo-scanning electron microscopy (SEM). After topical application, only the Trio formulation profoundly increased lateral packing of lipids and their compactness. Cryo-SEM showed that, unlike the placebo formulation, the Trio formulation prevented the water loss when applied before the dehydration process. In conclusion, these studies demonstrate that stresses in the SC due to dehydration can be alleviated using a formulation containing emollients that interact with the SC lipid components.

    View details for DOI 10.1111/exd.14331

    View details for PubMedID 33811391

  • Proceed with Caution: Mouse Deep Digit Flexor Tendon Injury Model. Plastic and reconstructive surgery. Global open Titan, A. L., Fahy, E. n., Chen, K. n., Foster, D. S., Bennett-Kennett, R. n., Dauskardt, R. H., Gurtner, G. C., Chang, J. n., Fox, P. M., Longaker, M. T. 2021; 9 (1): e3359

    Abstract

    The purpose of this study was to determine the feasibility of using mouse models for translational study of flexor tendon repair and reconstruction.Quantitative data detailing the gross anatomy, biomechanical characteristics, and microscopic structure of the deep digit flexor tendon (DDF) of the mouse hindpaw were obtained. Histological characterization of the DDF and the anatomy of the digit in the mouse hindpaw are detailed. Biomechanical testing determined the load-to-failure, stress, elastic modulus, and the site of tendon failure.In gross anatomy, the origins and insertions of the mouse deep digit flexor tendon are similar to those of the human digit, surrounded by a synovial sheath that is only 1- to 2-cells thick. A neurovascular network runs on each side of the digit outside the synovial sheath, but does not clearly penetrate it. The thickness of the DDF is 0.14 ± 0.03 mm and the width is 0.3 ± 0.03 mm. The thickness of the DDF is less than that of 9-0 nylon needle. The mean failure force of the deep flexor tendon was 2.79 ± 0.53N.The gross anatomy of the mouse hindpaw digit is similar to that of the human digit except for key differences seen in the synovial sheath and vascular supply. The dimensions of the mouse DDF make it challenging to create a clinically translatable repair model using currently available surgical techniques. Despite the similarities between the human and mouse anatomy, and the powerful basic science tools available in murine models, mice are an unreliable model for assessing flexor tendon injury and repair.

    View details for DOI 10.1097/GOX.0000000000003359

    View details for PubMedID 33552814

    View details for PubMedCentralID PMC7859083

  • Durability of Polyolefin Encapsulation in Photovoltaic Modules with SmartWire Technology Thornton, P., Tracy, J., Roraff, P., Choudhury, K., Dauskardt, R. H., IEEE IEEE. 2021: 1170-1172
  • Rapid Open-Air Processing of Low-Cost Perovskite Solar Modules Rolston, N., Scheideler, W. J., Flick, A., Chen, J. P., Elmaraghi, H., Sleugh, A., Zhao, O., Woodhouse, M., Dauskardt, R. H., IEEE IEEE. 2021: 88-91
  • Rapid Open-Air Fabrication of Perovskite Solar Modules JOULE Rolston, N., Scheideler, W. J., Flick, A. C., Chen, J. P., Elmaraghi, H., Sleugh, A., Zhao, O., Woodhouse, M., Dauskardt, R. H. 2020; 4 (12): 2675–92
  • Scalable open-air deposition of compact ETL TiOx on perovskite for fullerene-free solar cells JOURNAL OF MATERIALS CHEMISTRY A Chen, J. P., Hilt, F., Rolston, N., Dauskardt, R. H. 2020; 8 (43): 22858–66

    View details for DOI 10.1039/d0ta08554e

    View details for Web of Science ID 000589418400032

  • Mechanically reliable hybrid organosilicate glasses for advanced interconnects JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Kilic, K., Dauskardt, R. H. 2020; 38 (6)

    View details for DOI 10.1116/6.0000517

    View details for Web of Science ID 000582508400001

  • Lipid Loss Increases Stratum Corneum Stress and Drying Rates. Skin pharmacology and physiology Bow, J. R., Sonoki, Y., Uchiyama, M., Shimizu, E., Tanaka, K., Dauskardt, R. H. 2020: 1–9

    Abstract

    BACKGROUND: The lipid components and natural moisturizing factors (NMFs) of the stratum corneum (SC) are integral pieces of the self-regulating barrier strategy which comprises one of the most important functions of human skin and seems to be related to biomechanical responses of the SC.OBJECTIVES: This work presents the contributions of the lipid bilayers and NMFs to the barrier properties and mechanical responses of human SC.METHODS: We performed 2 biomechanical experiments, substrate curvature testing and double cantilever beam cohesion measurements, on isolated human SC exposed to either water, a 1:1 mixture of acetone/ether, or a 1:1 mixture of chloroform/methanol for various durations.RESULTS: We show that treating ex vivo SC with organic solvents results in lipid extraction which increases with duration of exposure. This extraction is tied to a remarkably linear increase in the levels and rates of biaxial stress development during drying/hydration cycles. This effect appears to be tied to the total amounts of lipids extracted. Furthermore, striking changes are seen in the intercellular cohesion properties of the tissue after solvent exposure. Interestingly, changes in drying stress profiles are not observed after treatment with water, which has been previously shown to remove NMFs from the tissue, and which therefore might be expected to induce changes in the drying behavior of the skin. However, changes in intercellular cohesion and the SC cohesion gradient are seen, suggesting impacts on the corneodesmosome protein binding junctions within the tissue.CONCLUSIONS: These results suggest that lipid loss causes marked increases in SC drying stresses, which may in turn contribute to changes in skin perception. NMF extraction may be important in vivo, but has remarkably little impact in isolated SC.

    View details for DOI 10.1159/000507456

    View details for PubMedID 32882700

  • Self-aligned concentrating immersion-lens arrays for patterning and efficiency recovery in scaffold-reinforced perovskite solar cells APPLIED MATERIALS TODAY Printz, A. D., Zhao, O., Hamann, S., Rolston, N., Solgaard, O., Dauskardt, R. H. 2020; 20
  • Fully stretchable active-matrix organic light-emitting electrochemical cell array. Nature communications Liu, J., Wang, J., Zhang, Z., Molina-Lopez, F., Wang, G. N., Schroeder, B. C., Yan, X., Zeng, Y., Zhao, O., Tran, H., Lei, T., Lu, Y., Wang, Y., Tok, J. B., Dauskardt, R., Chung, J. W., Yun, Y., Bao, Z. 2020; 11 (1): 3362

    Abstract

    Intrinsically and fully stretchable active-matrix-driven displays are an important element to skin electronics that can be applied to many emerging fields, such as wearable electronics, consumer electronics and biomedical devices. Here, we show for the first time a fully stretchable active-matrix-driven organic light-emitting electrochemical cell array. Briefly, it is comprised of a stretchable light-emitting electrochemical cell array driven by a solution-processed, vertically integrated stretchable organic thin-film transistor active-matrix, which is enabled by the development of chemically-orthogonal and intrinsically stretchable dielectric materials. Our resulting active-matrix-driven organic light-emitting electrochemical cell array can be readily bent, twisted and stretched without affecting its device performance. When mounted on skin, the array can tolerate to repeated cycles at 30% strain. This work demonstrates the feasibility of skin-applicable displays and lays the foundation for further materials development.

    View details for DOI 10.1038/s41467-020-17084-w

    View details for PubMedID 32620794

  • Effect of Emulsifiers on Drying Stress and Intercellular Cohesion in Human Stratum Corneum. International journal of cosmetic science Ansari, F., McGuiness, C., Zhang, B., Dauskardt, R. H. 2020

    Abstract

    OBJECTIVES: Emulsifier molecules, with their amphiphilic character, are ubiquitous in moisturizing creams and primarily serve to disperse the water-insoluble molecules such as emollients, oils, lipids, and fats in water. The objective of this study was to investigate the effect of emulsifier molecules on the barrier and biomechanical properties of human stratum corneum (SC), and to compare the efficacy of emulsifier molecules when used in a fully formulated moisturizing cream.METHODS: We employed methods based on thin film mechanics to measure the drying stress and intercellular cohesion in the SC. The emulsifier molecules or moisturizing creams formulated with them were applied to a fully-hydrated SC adhered to a glass substrate. In-plane stress developed in the SC during drying was measured by tracking changes in the curvature of the glass substrate. The intercellular cohesion within the SC was measured by means of a double cantilever beam (DCB) setup, where the treated or untreated SC was sandwiched between two substrates, and the delamination energy calculated by measuring the force required to drive a crack through the SC. Moisturizing cream diffusivity through the stratum corneum was measured by spectroscopic technique, and related to internal SC stress and fracture energy.RESULTS: We observe significant differences in the biomechanical behaviour of SC when moisturizing creams with different emulsifier molecules are applied on isolated stratum corneum ex vivo. The reduction in maximum stress varied between 12% and 26% depending on the emulsifier molecules used in the formulation. The intercellular cohesion as well as the diffusion of molecules in the formulated moisturizing creams through the SC were also found to be strongly dependent on the type of emulsifier molecule used in the formulation.CONCLUSIONS: The biomechanical and barrier properties of the human stratum corneum show strong dependence on the emulsifier molecule used in the moisturizing creams, even when the creams included only ~3 weight% emulsifier molecules. Moreover, we found that the reduction in SC peak stress was strongly correlated with the formulation diffusivity into the SC. The moisturizing creams diffusing fastest into the SC had the largest reduction in peak stress and vice versa.

    View details for DOI 10.1111/ics.12643

    View details for PubMedID 32567061

  • Perspectives on intrinsic toughening strategies and passivation of perovskite films with organic additives SOLAR ENERGY MATERIALS AND SOLAR CELLS Gutwald, M., Rolston, N., Printz, A. D., Zhao, O., Elmaraghi, H., Ding, Y., Zhang, J., Dauskardt, R. H. 2020; 209
  • Durability of ionomer encapsulants in photovoltaic modules SOLAR ENERGY MATERIALS AND SOLAR CELLS Tracy, J., Bosco, N., Delgado, C., Dauskardt, R. 2020; 208
  • Multiaxial Lenticular Stress-Strain Relationship of Native Myocardium is Preserved by Infarct-Induced Natural Heart Regeneration in Neonatal Mice. Scientific reports Wang, H., Bennett-Kennett, R., Paulsen, M. J., Hironaka, C. E., Thakore, A. D., Farry, J. M., Eskandari, A., Lucian, H. J., Shin, H. S., Wu, M. A., Imbrie-Moore, A. M., Steele, A. N., Stapleton, L. M., Zhu, Y., Dauskardt, R. H., Woo, Y. J. 2020; 10 (1): 7319

    Abstract

    Neonatal mice exhibit natural heart regeneration after myocardial infarction (MI) on postnatal day 1 (P1), but this ability is lost by postnatal day 7 (P7). Cardiac biomechanics intricately affect long-term heart function, but whether regenerated cardiac muscle is biomechanically similar to native myocardium remains unknown. We hypothesized that neonatal heart regeneration preserves native left ventricular (LV) biomechanical properties after MI. C57BL/6J mice underwent sham surgery or left anterior descending coronary artery ligation at age P1 or P7. Echocardiography performed 4 weeks post-MI showed that P1 MI and sham mice (n=22, each) had similar LV wall thickness, diameter, and ejection fraction (59.6% vs 60.7%, p=0.6514). Compared to P7 shams (n=20), P7 MI mice (n=20) had significant LV wall thinning, chamber enlargement, and depressed ejection fraction (32.6% vs 61.8%, p<0.0001). Afterward, the LV was explanted and pressurized ex vivo, and the multiaxial lenticular stress-strain relationship was tracked. While LV tissue modulus for P1 MI and sham mice were similar (341.9 kPa vs 363.4 kPa, p=0.6140), the modulus for P7 MI mice was significantly greater than that for P7 shams (691.6 kPa vs 429.2 kPa, p=0.0194). We conclude that, in neonatal mice, regenerated LV muscle has similar biomechanical properties as native LV myocardium.

    View details for DOI 10.1038/s41598-020-63324-w

    View details for PubMedID 32355240

  • Comment on "Light-induced lattice expansion leads to high-efficiency perovskite solar cells". Science (New York, N.Y.) Rolston, N., Bennett-Kennett, R., Schelhas, L. T., Luther, J. M., Christians, J. A., Berry, J. J., Dauskardt, R. H. 2020; 368 (6488)

    Abstract

    Tsai et al (Reports, 6 April 2018, p. 67) report a uniform light-induced lattice expansion of metal halide perovskite films under 1-sun illumination and claim to exclude heat-induced lattice expansion. We show that by controlling the temperature of the perovskite film under both dark and illuminated conditions, the mechanism for lattice expansion is in fact fully consistent with heat-induced thermal expansion during illumination.

    View details for DOI 10.1126/science.aay8691

    View details for PubMedID 32299922

  • Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy. Advanced materials (Deerfield Beach, Fla.) Hu, B., Berkey, C., Feliciano, T., Chen, X., Li, Z., Chen, C., Amini, S., Nai, M. H., Lei, Q., Ni, R., Wang, J., Leow, W. R., Pan, S., Li, Y., Cai, P., Miserez, A., Li, S., Lim, C. T., Wu, Y., Odom, T. W., Dauskardt, R. H., Chen, X. 2020: e1907030

    Abstract

    Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.

    View details for DOI 10.1002/adma.201907030

    View details for PubMedID 32072703

  • Crystallization kinetics of rapid spray plasma processed multiple cation perovskites in open air JOURNAL OF MATERIALS CHEMISTRY A Hovish, M. Q., Rolston, N., Bruning, K., Hilt, F., Tassone, C., Dauskardt, R. H. 2020; 8 (1): 169–76

    View details for DOI 10.1039/c9ta07980g

    View details for Web of Science ID 000503772400012

  • Open-Air Plasma-Deposited Multilayer Thin-Film Moisture Barriers. ACS applied materials & interfaces Zhao, O. n., Ding, Y. n., Pan, Z. n., Rolston, N. n., Zhang, J. n., Dauskardt, R. H. 2020

    Abstract

    Emerging moisture sensitive devices require robust encapsulation strategies to inhibit water ingress and prevent premature failure. A scalable, open-air plasma process has been developed to deposit alternating layers of conformal organosilicate and dense SiO2 thin-film barriers to prevent moisture ingress. The in situ low-temperature process is suitable for direct deposition on thermally sensitive devices and is compatible with flexible polymeric substrates. Using optical calcium testing, low water vapor transmission rates on the order of 10-3 g/m2/day at an accelerated aging condition of 38 °C and 90% relative humidity (RH) are achieved. Using moisture-sensitive perovskite devices as a representative moisture-susceptible device, devices retain over 80% of their initial performance for over 660 h in a 50 °C 50% RH accelerated aging environment. The ability of the multilayer barrier to enable device resistance to humid environments is crucial toward realizing longer operating lifetimes.

    View details for DOI 10.1021/acsami.0c01493

    View details for PubMedID 32403921

  • Open-Air Plasma-Deposited Multilayer Thin Film Moisture Barriers for Perovskite Solar Cells Zhao, O., Ding, Y., Pan, Z., Rolston, N., Zhang, J., Dauskardt, R. H., IEEE IEEE. 2020: 2430-2432
  • Emollient Structure and Chemical Functionality Effects on the Biomechanical Function of Human Stratum Corneum. International journal of cosmetic science Berkey, C. n., Kanno, D. n., Mehling, A. n., Koch, J. P., Eisfeld, W. n., Dierker, M. n., Bhattacharya, S. n., Dauskardt, R. H. 2020

    Abstract

    Cosmetic emollients are commonly used ingredients in cosmetic or skin moisturizing treatments as they enhance formulation spreadability and feel while improving skin barrier function. These molecules are typically long-chain organic molecules containing small, polar functional groups, but they may have differences in structure or chemical functionality. The term "emollient" is used to describe, depending on context, various compounds including exogenous and physiologic lipids, humectants, anti-pruritics, and materials that support cell metabolism. In this work we focus on "cosmetic emollients", i.e. the topically applied "oils" typically used in cosmetic formulations - as opposed to "dermatological emollients" which may refer to any number of fully formulated dermatological skin care treatments. During application, cosmetic emollients may form an oily partially occlusive film on the skin surface which reduces total trans epidermal water loss (TEWL) and helps spread other formulation ingredients.

    View details for DOI 10.1111/ics.12656

    View details for PubMedID 32794598

  • An Intrinsically Stretchable High-Performance Polymer Semiconductor with Low Crystallinity ADVANCED FUNCTIONAL MATERIALS Zheng, Y., Wang, G., Kang, J., Nikolka, M., Wu, H., Tran, H., Zhang, S., Yan, H., Chen, H., Yuen, P., Mun, J., Dauskardt, R. H., McCulloch, I., Tok, J., Gu, X., Bao, Z. 2019
  • Role of sunscreen formulation and photostability to protect the biomechanical barrier function of skin. Biochemistry and biophysics reports Berkey, C., Oguchi, N., Miyazawa, K., Dauskardt, R. 2019; 19: 100657

    Abstract

    The impact of sunscreen formulations on the barrier properties of human skin are often overlooked leading to formulations with components whose effects on barrier mechanical integrity are poorly understood. The aim of this study is to demonstrate the relevance of carrier selection and sunscreen photostability when designing sunscreen formulations to protect the biomechanical barrier properties of human stratum corneum (SC) from solar ultraviolet (UV) damage. Biomechanical properties of SC samples were assayed after accelerated UVB damage through measurements of the SC's mechanical stress profile and corneocyte cohesion. A narrowband UVB (305-315 nm) lamp was used to expose SC samples to 5, 30, 125, and 265 J cm-2 in order to magnify damage to the mechanical properties of the tissue and characterize the UV degradation dose response such that effects from smaller UV dosages can be extrapolated. Stresses in the SC decreased when treated with sunscreen components, highlighting their effect on the skin prior to UV exposure. Stresses increased with UVB exposure and in specimens treated with different sunscreens stresses varied dramatically at high UVB dosages. Specimens treated with sunscreen components without UVB exposure exhibited altered corneocyte cohesion. Both sunscreens studied prevented alteration of corneocyte cohesion by low UVB dosages, but differences in protection were observed at higher UVB dosages indicating UV degradation of one sunscreen. These results indicate the protection of individual sunscreen components vary over a range of UVB dosages, and components can even cause alteration of the biomechanical barrier properties of human SC before UV exposure. Therefore, detailed characterization of sunscreen formulation components is required to design robust protection from UV damage.

    View details for DOI 10.1016/j.bbrep.2019.100657

    View details for PubMedID 31211250

  • High-performance hybrids at the extreme limits of molecular-scale confinement Dauskardt, R. AMER CHEMICAL SOC. 2019
  • Design of Ultrastiff Organosilicate Hybrid Glasses ADVANCED FUNCTIONAL MATERIALS Kilic, K., Dauskardt, R. H. 2019
  • Neonatal Heart Regeneration Preserves Native Ventricular Biomechanical Properties After Myocardial Infarction Wang, H., Bennett-Kennett, R., Paulsen, M. J., Hironaka, C. E., Thakore, A. D., Farry, J. M., Eskandari, A., Lucian, H. J., Wu, M. A., Imbrie-Moore, A., Steele, A. N., Stapleton, L. M., Dauskardt, R. H., Woo, Y. LIPPINCOTT WILLIAMS & WILKINS. 2019
  • Surface Chemical Functionalization to Achieve Extreme Levels of Molecular Confinement in Hybrid Nanocomposites ADVANCED FUNCTIONAL MATERIALS Wang, C., Isaacson, S. C., Wang, Y., Lionti, K., Volksen, W., Magbitang, T. P., Chowdhury, M., Priestley, R. D., Dubois, G., Dauskardt, R. H. 2019; 29 (33)
  • Tearing and reliability of photovoltaic module backsheets PROGRESS IN PHOTOVOLTAICS Yuen, P., Moffitt, S. L., Novoa, F. D., Schelhas, L. T., Dauskardt, R. H. 2019; 27 (8): 693–705

    View details for DOI 10.1002/pip.3144

    View details for Web of Science ID 000476821500004

  • Hole-Transport Layer Molecular Weight and Doping Effects on Perovskite Solar Cell Efficiency and Mechanical Behavior ACS APPLIED MATERIALS & INTERFACES Lee, I., Rolston, N., Brunner, P., Dauskardt, R. H. 2019; 11 (26): 23757–64

    Abstract

    The effect of tuning molecular weight ( Mn) in poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) to increase both mechanical properties of the film and electrical properties of perovskite solar cells is reported. Perovskite solar cell devices are fabricated to investigate the effect of Mn on power conversion efficiency. Moisture stability for various Mn is also studied in PTAA films exposed to mechanical loads in humid environments. Furthermore, cohesion and tensile tests are employed to determine the mechanical properties of PTAA, where higher Mn leads to more robust films. To elucidate the effect of Mn on the debonding kinetics, a viscoelastic fracture kinetic model is proposed as a function of Mn, and the debonding mechanism is found to be dependent on Mn. Finally, the effect of small-molecule-based dopants on the mechanical stability of PTAA is investigated.

    View details for DOI 10.1021/acsami.9b05567

    View details for Web of Science ID 000474670100092

    View details for PubMedID 31184460

  • Open Air Plasma Deposition of Superhydrophilic Titania Coatings ADVANCED FUNCTIONAL MATERIALS Hovish, M. Q., Hilt, F., Rolston, N., Xiao, I., Dauskardt, R. H. 2019; 29 (19)
  • Rapid Aqueous Spray Fabrication of Robust NiOx: A Simple and Scalable Platform for Efficient Perovskite Solar Cells ADVANCED ENERGY MATERIALS Scheideler, W. J., Rolston, N., Zhao, O., Zhang, J., Dauskardt, R. H. 2019; 9 (19)
  • Molecular design and engineering of hybrids at the extreme limits of molecular-scale confinement Dauskardt, R. AMER CHEMICAL SOC. 2019
  • Environmental Influence on Module Delamination Rate IEEE JOURNAL OF PHOTOVOLTAICS Bosco, N., Tracy, J., Dauskardt, R. 2019; 9 (2): 469–75
  • Framework for predicting the photodegradation of adhesion of silicone encapsulants SOLAR ENERGY MATERIALS AND SOLAR CELLS Cai, C., Miller, D. C., Tappan, I. A., Dauskardt, R. H. 2019; 191: 486–92
  • High Performance Roll-to-Roll Produced Fullerene-Free Organic Photovoltaic Devices via Temperature-Controlled Slot Die Coating ADVANCED FUNCTIONAL MATERIALS Na, S., Seo, Y., Nah, Y., Kim, S., Heo, H., Kim, J., Rolston, N., Dauskardt, R. H., Gao, M., Lee, Y., Vak, D. 2019; 29 (6)
  • Understanding PV Polymer Backsheet Degradation through X-ray Scattering Moffitt, S. L., Yuen, P., Owen-Bellini, M., Miller, D. C., Jenket, D. R., Maes, A. M., Hartley, J. Y., Sinha, A., Karin, T., Hacke, P., Dauskardt, R. H., Schelhas, L. T., IEEE IEEE. 2019: 2394–97
  • Evaluating and predicting molecular mechanisms of adhesive degradation during field and accelerated aging of photovoltaic modules PROGRESS IN PHOTOVOLTAICS Tracy, J., D'hooge, D. R., Bosco, N., Delgado, C., Dauskardt, R. 2018; 26 (12): 981–93

    View details for DOI 10.1002/pip.3045

    View details for Web of Science ID 000450333300004

  • High-Throughput Open-Air Plasma Activation of Metal-Oxide Thin Films with Low Thermal Budget ACS APPLIED MATERIALS & INTERFACES Tak, Y., Hilt, F., Keene, S., Kim, W., Dauskardt, R. H., Salleo, A., Kim, H. 2018; 10 (43): 37223–32

    Abstract

    Sputter-processed oxide films are typically annealed at high temperature (activation process) to achieve stable electrical characteristics through the formation of strong metal-oxide chemical bonds. For instance, indium-gallium-zinc oxide (IGZO) films typically need a thermal treatment at 300 °C for ≥1 h as an activation process. We propose an open-air plasma treatment (OPT) to rapidly and effectively activate sputter-processed IGZO films. The OPT effectively induces metal-oxide chemical bonds in IGZO films at temperatures as low as 240 °C, with a dwell time on the order of a second. Furthermore, by controlling the plasma-processing conditions (scan speed, distance a between plasma nozzle and samples, and gas flow rate), the electrical characteristics and the microstructure of the IGZO films can be easily tuned. Finally, OPT can be utilized to implement a selective activation process. Plasma-treated IGZO thin-film transistors (TFTs) exhibit comparable electrical characteristics to those of conventionally thermal treated IGZO TFTs. Through in-depth optical, chemical, and physical characterizations, we confirm that OPT simultaneously dissociates weak chemical bonds by UV radiation and ion bombardment and re-establishes the metal-oxide network by radical reaction and OPT-induced heat.

    View details for PubMedID 30288973

  • The Role of Catalyst Adhesion in ALD-TiO2 Protection of Water Splitting Silicon Anodes. ACS applied materials & interfaces Tang-Kong, R., Winter, R., Brock, R., Tracy, J., Eizenberg, M., Dauskardt, R. H., McIntyre, P. C. 2018

    Abstract

    Atomic layer deposited titanium dioxide (ALD-TiO2) has emerged as an effective protection layer for highly efficient semiconductor anodes which are normally unstable under the potential and pH conditions used to oxidize water in a photoelectrochemical cell. The failure modes of silicon anodes coated with an Ir/IrO x oxygen evolution catalyst layer are investigated, and poor catalyst/substrate adhesion is found to be a key factor in failed anodes. Quantitative measurements of interfacial adhesion energy show that the addition of TiO2 significantly improves reliability of anodes, yielding an adhesion energy of 6.02 ± 0.5 J/m2, more than double the adhesion energy measured in the absence of an ALD-TiO2 protection layer. These results indicate the importance of catalyst adhesion to an interposed protection layer in promoting operational stability of high efficiency semiconducting anodes during solar-driven water splitting.

    View details for PubMedID 30346686

  • Engineering Stress in Perovskite Solar Cells to Improve Stability ADVANCED ENERGY MATERIALS Rolston, N., Bush, K. A., Printz, A. D., Gold-Parker, A., Ding, Y., Toney, M. F., McGehee, M. D., Dauskardt, R. H. 2018; 8 (29)
  • A novel micro-double cantilever beam (micro-DCB) test in an X-ray microscope to study crack propagation in materials and structures MATERIALS TODAY COMMUNICATIONS Kutukova, K., Niese, S., Gelb, J., Dauskardt, R., Zschech, E. 2018; 16: 293–99
  • Opportunities and challenges for reliable flexible and stretchable polymer devices Dauskardt, R. AMER CHEMICAL SOC. 2018
  • Open-air spray plasma deposited UV-absorbing nanocomposite coatings NANOSCALE Ding, Y., Dong, S., Hilt, F., Dauskardt, R. H. 2018; 10 (30): 14525–33

    View details for DOI 10.1039/c8nr04095h

    View details for Web of Science ID 000441583400015

  • Using Unentangled Oligomers To Toughen Materials. ACS applied materials & interfaces Isaacson, S. G., Matsuda, Y., Lionti, K., Frot, T., Volksen, W., Dauskardt, R. H., Dubois, G. 2018

    Abstract

    Entanglements between polymer chains are responsible for the strength and toughness of polymeric materials. When the chains are too short to form entanglements, the polymer becomes weak and brittle. Here we show that molecular bridging of oligomers in molecular-scale confinement can dramatically toughen materials even when intermolecular entanglements are completely absent. We describe the fabrication of nanocomposite materials that confine oligomer chains to molecular-scale dimensions and demonstrate that partially confined unentangled oligomers can toughen materials far beyond rule-of-mixtures estimates. We also characterize how partially confined oligomers affect the kinetics of nanocomposite cracking in moist environments and show that the presence of a backfilled oligomeric phase within a nanoporous organosilicatematrix leads to atomistic crack path meandering in which the failure path is preferentially located within the matrix phase.

    View details for PubMedID 30074761

  • A Silica-Aerogel-Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus ADVANCED MATERIALS Lin, D., Yuen, P., Liu, Y., Liu, W., Liu, N., Dauskardt, R. H., Cui, Y. 2018; 30 (32)
  • Rapid route to efficient, scalable, and robust perovskite photovoltaics in air ENERGY & ENVIRONMENTAL SCIENCE Hilt, F., Hovish, M. Q., Rolston, N., Bruening, K., Tassone, C. J., Dauskardt, R. H. 2018; 11 (8): 2102–13

    View details for DOI 10.1039/c8ee01065j

    View details for Web of Science ID 000442262900018

  • Influence of Bulky Organo-Ammonium Halide Additive Choice on the Flexibility and Efficiency of Perovskite Light-Emitting Devices ADVANCED FUNCTIONAL MATERIALS Zhao, L., Rolston, N., Lee, K., Zhao, X., Reyes-Martinez, M. A., Tran, N. L., Yeh, Y., Yao, N., Scholes, G. D., Loo, Y., Selloni, A., Dauskardt, R. H., Rand, B. P. 2018; 28 (31)
  • Open-air spray plasma deposited UV-absorbing nanocomposite coatings. Nanoscale Ding, Y., Dong, S., Hilt, F., Dauskardt, R. H. 2018

    Abstract

    We demonstrate the deposition of mechanically robust UV-absorbing nanocomposite coatings with a newly developed dual-source deposition method involving ultrasonic spraying and open-air plasma deposition. Nanoparticles and the coating matrix are independently deposited which eliminates difficulties associated with preparing composites with high mass fraction of well-dispersed nanoparticles in the matrix. Nanocomposite coatings containing different concentrations of silica, ceria, and both titania and ceria nanoparticles were successfully deposited with good nanoparticle dispersity, high transparency over the visible range, effective absorption in the UV wavelength, and enhanced mechanical properties. Moreover, films were successfully deposited on several substrates including polycarbonate to demonstrate the low processing temperature of this dual-source deposition method. Coatings with different nanoparticle concentrations and film thicknesses were systematically studied in terms of their surface morphology, optical properties and mechanical properties. Accelerated photostability testing of the UV-absorbing nanocomposites demonstrates significantly enhanced performance compared to existing coatings with either a polymeric matrix or organic UV-absorbers.

    View details for PubMedID 30024014

  • Electrically Conductive Copper Core-Shell Nanowires through Benzenethiol-Directed Assembly. Nano letters Xiao, Q., Burg, J. A., Zhou, Y., Yan, H., Wang, C., Ding, Y., Reed, E., Miller, R. D., Dauskardt, R. H. 2018

    Abstract

    Ultrathin nanowires with <3 nm diameter have long been sought for novel properties that emerge from dimensional constraint as well as for continued size reduction and performance improvement of nanoelectronic devices. Here, we report on a facile and large-scale synthesis of a new class of electrically conductive ultrathin core-shell nanowires using benzenethiols. Core-shell nanowires are atomically precise and have inorganic five-atom copper-sulfur cross-sectional cores encapsulated by organic shells encompassing aromatic substituents with ring planes oriented parallel. The exact nanowire atomic structures were revealed via a two-pronged approach combining computational methods coupled with experimental synthesis and advanced characterizations. Core-shell nanowires were determined to be indirect bandgap materials with a predicted room-temperature resistivity of 120 Omega·m. Nanowire morphology was found to be tunable by changing the interwire interactions imparted by the functional group on the benzenethiol molecular precursors, and the nanowire core diameter was determined by the steric bulkiness of the ligand. These discoveries help define our understanding of the fundamental constituents of atomically well-defined and electrically conductive core-shell nanowires, representing significant advances toward nanowire building blocks for smaller, faster, and more powerful nanoelectronics.

    View details for PubMedID 29985626

  • Beyond Fullerenes: Indacenodithiophene-Based Organic Charge-Transport Layer toward Upscaling of Low-Cost Perovskite Solar Cells ACS APPLIED MATERIALS & INTERFACES Angmo, D., Peng, X., Cheng, J., Gao, M., Rolston, N., Sears, K., Zuo, C., Subbiah, J., Kim, S., Weerasinghe, H., Dauskardt, R. H., Vak, D. 2018; 10 (26): 22143–55

    Abstract

    Phenyl-C61-butyric acid methyl ester (PCBM) is universally used as the electron-transport layer (ETL) in the low-cost inverted planar structure of perovskite solar cells (PeSCs). PCBM brings tremendous challenges in upscaling of PeSCs using industry-relevant methods due to its aggregation behavior, which undermines the power conversion efficiency and stability. Herein, we highlight these, seldom reported, challenges with PCBM. Furthermore, we investigate the potential of nonfullerene indacenodithiophene (IDT)-based molecules by employing a commercially available variant, 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3- d:2',3'- d']- s-indaceno[1,2- b:5,6- b'] dithiophene (ITIC), as a PCBM replacement in ambient-processed PeSCs. Films fabrication by laboratory-based spin-coating and industry-relevant slot-die coating methods are compared. Although similar power-conversion efficiencies are achieved with both types of ETL in a simple device structure fabricated by spin-coating, the nanofibriller morphology of ITIC compared to the aggregated morphology of PCBM films enables improved mechanical integrity and stability of ITIC devices. Upon slot-die coating, the aggregation of PCBM is exacerbated, leading to significantly lower power-conversion efficiency of devices than spin-coated PCBM as well as slot-die-coated ITIC devices. Our results clearly indicate that IDT-based molecules have great potential as an ETL in PeSCs, offering superior properties and upscaling compatibility than PCBM. Thus, we present a short summary of recently emerged nonfullerene IDT-based molecules from the field of organic solar cells and discuss their scope in PeSCs as electron or hole-transport layer.

    View details for PubMedID 29877699

  • A Silica-Aerogel-Reinforced Composite Polymer Electrolyte with High Ionic Conductivity and High Modulus. Advanced materials (Deerfield Beach, Fla.) Lin, D., Yuen, P. Y., Liu, Y., Liu, W., Liu, N., Dauskardt, R. H., Cui, Y. 2018: e1802661

    Abstract

    High-energy all-solid-state lithium (Li) batteries have great potential as next-generation energy-storage devices. Among all choices of electrolytes, polymer-based systems have attracted widespread attention due to their low density, low cost, and excellent processability. However, they are generally mechanically too weak to effectively suppress Li dendrites and have lower ionic conductivity for reasonable kinetics at ambient temperature. Herein, an ultrastrong reinforced composite polymer electrolyte (CPE) is successfully designed and fabricated by introducing a stiff mesoporous SiO2 aerogel as the backbone for a polymer-based electrolyte. The interconnected SiO2 aerogel not only performs as a strong backbone strengthening the whole composite, but also offers large and continuous surfaces for strong anion adsorption, which produces a highly conductive pathway across the composite. As a consequence, a high modulus of 0.43 GPa and high ionic conductivity of 0.6 mS cm-1 at 30 °C are simultaneously achieved. Furthermore, LiFePO4 -Li full cells with good cyclability and rate capability at ambient temperature are obtained. Full cells with cathode capacity up to 2.1 mAh cm-2 are also demonstrated. The aerogel-reinforced CPE represents a new design principle for solid-state electrolytes and offers opportunities for future all-solid-state Li batteries.

    View details for PubMedID 29939433

  • Measurement of the Biomechanical Function and Structure of Ex Vivo Drying Skin Using Raman Spectral Analysis and its Modulation with Emollient Mixtures. Experimental dermatology Biniek, K., Tfayli, A., Vyumvuhore, R., Quatela, A., Galliano, M., Delalleau, A., Baillet-Guffroy, A., Dauskardt, R. H., Duplan, H. 2018

    Abstract

    An important aspect of the biomechanical behavior of the stratum corneum (SC) is the drying stresses that develop with water loss. These stresses act as a driving force for damage in the form of chapping and cracking. Betasitosterol is a plant sterol with a structure similar to cholesterol, a key component in the intercellular lipids of the outermost layer of human skin, the SC. Cholesterol plays an important role in stabilizing the SC lipid structure, and altered levels of cholesterol have been linked with SC barrier abnormalities. Betasitosterol is currently applied topically to skin for treatment of wounds and burns. However, it is unknown what effect betasitosterol has on the biomechanical barrier function of skin. Here, by analyzing the drying stress profile of SC generated during a kinetics of dehydration, we show that betasitosterol, in combination with two emollient molecules, isocetyl stearoyl stearate (ISS) and glyceryl tri-2-ethylhexanoate (GTEH), causes a significant modulation of the drying stress behavior of the SC by reducing both the maximal peak stress height and average plateau of the drying stress profile. Raman spectra analyses demonstrate that the combination of betasitosterol with the two emollients, ISS and GTEH, allows a high water retention capacity within the SC, while the lipid conformational order by increasing the amount of trans conformers. Our study highlights the advantage of combining a biomechanical approach together with Raman spectroscopy in engineering a suitable combination of molecules for alleviating dryness and dry skin damage. This article is protected by copyright. All rights reserved.

    View details for PubMedID 29933507

  • Toward Sustainable Multifunctional Coatings Containing Nanocellulose in a Hybrid Glass Matrix. ACS nano Ansari, F., Ding, Y., Berglund, L. A., Dauskardt, R. H. 2018

    Abstract

    We report on a sustainable route to protective nanocomposite coatings, where one of the components, nanocellulose fibrils, is derived from trees and the glass matrix is an inexpensive sol-gel organic-inorganic hybrid of zirconium alkoxide and an epoxy-functionalized silane. The hydrophilic nature of the colloidal nanocellulose fibrils is exploited to obtain a homogeneous one-pot suspension of the nanocellulose in the aqueous sol-gel matrix precursors solution. The mixture is then sprayed to form nanocomposite coatings of a well-dispersed, random in-plane nanocellulose fibril network in a continuous organic-inorganic glass matrix phase. The nanocellulose incorporation in the sol-gel matrix resulted in nanostructured composites with marked effects on salient coating properties including optical transmittance, hardness, fracture energy, and water contact angle. The particular role of the nanocellulose fibrils on coating fracture properties, important for coating reliability, was analyzed and discussed in terms of fibril morphology, molecular matrix, and nanocellulose/matrix interactions.

    View details for PubMedID 29882658

  • Controlling Thin-Film Stress and Wrinkling during Perovskite Film Formation ACS ENERGY LETTERS Bush, K. A., Rolston, N., Gold-Parker, A., Manzoor, S., Hausele, J., Yu, Z. J., Raiford, J. A., Cheacharoen, R., Holman, Z. C., Toney, M. F., Dauskardt, R. H., McGehee, M. D. 2018; 3 (6): 1225–32
  • Degradation of multijunction photovoltaic gridlines induced via thermal cycling SOLAR ENERGY MATERIALS AND SOLAR CELLS Brock, R. E., Hebert, P., Ermer, J., Dauskardt, R. H. 2018; 179: 178–84
  • Optically Transparent Protective Coating for Plastics Using Dual Spray and Atmospheric Plasma Deposition ADVANCED MATERIALS INTERFACES Ding, Y., Dong, S., Han, J., He, D., Zhao, Z., Dauskardt, R. H. 2018; 5 (9)
  • Effect of Cation Composition on the Mechanical Stability of Perovskite Solar Cells ADVANCED ENERGY MATERIALS Rolston, N., Printz, A. D., Tracy, J. M., Weerasinghe, H. C., Vak, D., Haur, L., Priyadarshi, A., Mathews, N., Slotcavage, D. J., McGehee, M. D., Kalan, R. E., Zielinski, K., Grimm, R. L., Tsai, H., Nie, W., Mohite, A. D., Gholipour, S., Saliba, M., Gratzel, M., Dauskardt, R. H. 2018; 8 (9)
  • Poly(triarylamine) composites with carbon nanomaterials for highly transparent and conductive coatings THIN SOLID FILMS Prolongo, S. G., Printz, A. D., Rolston, N., Watson, B. L., Dauskardt, R. H. 2018; 646: 61–66
  • Molecular design of confined organic network hybrids with controlled deformation rate sensitivity and moisture resistance ACTA MATERIALIA Ding, Y., Xiao, Q., Dauskardt, R. H. 2018; 142: 162–71
  • Spray Plasma Processing of Barrier Films Deposited in Air for Improved Stability of Flexible Electronic Devices Rolston, N., Printz, A. D., Hilt, F., Hovish, M. Q., Bruning, K., Tassone, C. J., Dauskardt, R. H., IEEE IEEE. 2018: 138–40
  • Nonaffine Deformations in ULK Dielectric Glasses Kilic, K. I., Dauskardt, R. H., IEEE IEEE. 2018: 58–60
  • Effect of Composition and Microstructure on the Mechanical Stability of Perovskite Solar Cells Rolston, N., Printz, A. D., Tracy, J. M., Dauskardt, R. H., IEEE IEEE. 2018: 3509–13
  • Damp Heat, Temperature Cycling and UV Stress Testing of Encapsulated Perovskite Photovoltaic Cells Cheacharoen, R., Bush, K. A., Rolston, N., Harwood, D., Dauskardt, R. H., McGehee, M. D., IEEE IEEE. 2018: 3498–3502
  • Framework for Modelling Interface Degradation in Photovoltaic Modules at the Molecular Level Tracy, J., D'hooge, D., Bosco, N., Dauskardt, R., IEEE IEEE. 2018: 3548–51
  • Design and understanding of encapsulated perovskite solar cells to withstand temperature cycling ENERGY & ENVIRONMENTAL SCIENCE Cheacharoen, R., Rolston, N., Harwood, D., Bush, K. A., Dauskardt, R. H., McGehee, M. D. 2018; 11 (1): 144–50

    View details for DOI 10.1039/c7ee02564e

    View details for Web of Science ID 000423017000013

  • Dense Vertically Aligned Copper Nanowire Composites as High Performance Thermal Interface Materials ACS APPLIED MATERIALS & INTERFACES Barako, M. T., Isaacson, S. G., Lian, F., Pop, E., Dauskardt, R. H., Goodson, K. E., Tice, J. 2017; 9 (48): 42067–74
  • Dense Vertically Aligned Copper Nanowire Composites as High Performance Thermal Interface Materials. ACS applied materials & interfaces Barako, M. T., Isaacson, S. G., Lian, F., Pop, E., Dauskardt, R. H., Goodson, K. E., Tice, J. 2017; 9 (48): 42067-42074

    Abstract

    Thermal interface materials (TIMs) are essential for managing heat in modern electronics, and nanocomposite TIMs can offer critical improvements. Here, we demonstrate thermally conductive, mechanically compliant TIMs based on dense, vertically aligned copper nanowires (CuNWs) embedded into polymer matrices. We evaluate the thermal and mechanical characteristics of 20-25% dense CuNW arrays with and without polydimethylsiloxane infiltration. The thermal resistance achieved is below 5 mm2 K W-1, over an order of magnitude lower than commercial heat sink compounds. Nanoindentation reveals that the nonlinear deformation mechanics of this TIM are influenced by both the CuNW morphology and the polymer matrix. We also implement a flip-chip bonding protocol to directly attach CuNW composites to copper surfaces, as required in many thermal architectures. Thus, we demonstrate a rational design strategy for nanocomposite TIMs that simultaneously retain the high thermal conductivity of aligned CuNWs and the mechanical compliance of a polymer.

    View details for DOI 10.1021/acsami.7b12313

    View details for PubMedID 29119783

  • Scaffold-reinforced perovskite compound solar cells ENERGY & ENVIRONMENTAL SCIENCE Watson, B. L., Rolston, N., Printz, A. D., Dauskardt, R. H. 2017; 10 (12): 2500–2508

    View details for DOI 10.1039/c7ee02185b

    View details for Web of Science ID 000417255900002

  • Improved stability and efficiency of perovskite solar cells with submicron flexible barrier films deposited in air JOURNAL OF MATERIALS CHEMISTRY A Rolston, N., Printz, A. D., Hilt, F., Hovish, M. Q., Bruning, K., Tassone, C. J., Dauskardt, R. H. 2017; 5 (44): 22975–83

    View details for DOI 10.1039/c7ta09178h

    View details for Web of Science ID 000415070100012

  • Engineering the Mechanical Properties of Polymer Networks with Precise Doping of Primary Defects. ACS applied materials & interfaces Chan, D., Ding, Y., Dauskardt, R. H., Appel, E. A. 2017

    Abstract

    Polymer networks are extensively utilized across numerous applications ranging from commodity superabsorbent polymers and coatings to high-performance microelectronics and biomaterials. For many applications, desirable properties are known; however, achieving them has been challenging. Additionally, the accurate prediction of elastic modulus has been a long-standing difficulty owing to the presence of loops. By tuning the prepolymer formulation through precise doping of monomers, specific primary network defects can be programmed into an elastomeric scaffold, without alteration of their resulting chemistry. The addition of these monomers that respond mechanically as primary defects is used both to understand their impact on the resulting mechanical properties of the materials and as a method to engineer the mechanical properties. Indeed, these materials exhibit identical bulk and surface chemistry, yet vastly different mechanical properties. Further, we have adapted the real elastic network theory (RENT) to the case of primary defects in the absence of loops, thus providing new insights into the mechanism for material strength and failure in polymer networks arising from primary network defects, and to accurately predict the elastic modulus of the polymer system. The versatility of the approach we describe and the fundamental knowledge gained from this study can lead to new advancements in the development of novel materials with precisely defined and predictable chemical, physical, and mechanical properties.

    View details for PubMedID 29135222

  • Synthesis of Polyimides in Molecular-Scale Confinement for Low-Density Hybrid Nanocomposites NANO LETTERS Isaacson, S. G., Fostvedt, J. I., Koerner, H., Baur, J. W., Lionti, K., Volksen, W., Dubois, G., Dauskardt, R. H. 2017; 17 (11): 7040–44

    Abstract

    In this work, we exploit a confinement-induced molecular synthesis and a resulting bridging mechanism to create confined polyimide thermoset nanocomposites that couple molecular confinement-enhanced toughening with an unprecedented combination of high-temperature properties at low density. We describe a synthesis strategy that involves the infiltration of individual polymer chains through a nanoscale porous network while simultaneous imidization reactions increase the molecular backbone stiffness. In the extreme limit where the confinement length scale is much smaller than the polymer's molecular size, confinement-induced molecular mechanisms give rise to exceptional mechanical properties. We find that polyimide oligomers can undergo cross-linking reactions even in such molecular-scale confinement, increasing the molecular weight of the organic phase and toughening the nanocomposite through a confinement-induced energy dissipation mechanism. This work demonstrates that the confinement-induced molecular bridging mechanism can be extended to thermoset polymers with multifunctional properties, such as excellent thermo-oxidative stability and high service temperatures (>350 °C).

    View details for PubMedID 28991490

  • Defining Threshold Values of Encapsulant and Backsheet Adhesion for PV Module Reliability IEEE JOURNAL OF PHOTOVOLTAICS Bosco, N., Eafanti, J., Kurtz, S., Tracy, J., Dauskardt, R. 2017; 7 (6): 1536–40
  • Encapsulant Adhesion to Surface Metallization on Photovoltaic Cells IEEE JOURNAL OF PHOTOVOLTAICS Tracy, J., Bosco, N., Dauskardt, R. 2017; 7 (6): 1635–39
  • Environmentally assisted crack growth in adhesively bonded composite joints COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING Tracy, J., Yin, Y., Yang, J., Osborne, J. C., Blohowiak, K. Y., Dauskardt, R. 2017; 102: 368–77
  • The Effects of Terminal Groups on Elastic Asymmetries in Hybrid Molecular Materials JOURNAL OF PHYSICAL CHEMISTRY B Burg, J. A., Dauskardt, R. H. 2017; 121 (41): 9753–59

    Abstract

    An asymmetric elastic modulus is a recently discovered and unexpected property of hybrid molecular materials that has significant implications for their underlying thermomechanical reliability. Elastic asymmetries are inherently related to terminal groups in the molecular structure, which limit network connectivity. Terminal groups sterically interact to stiffen the network in compression, while they disconnect the network and interact significantly less in tension. Here we study the importance of terminal group molecular weight and size (OH, methyl, vinyl, and phenyl) on the resulting elastic asymmetries and find that increasing the terminal group size actually leads to even larger degrees of asymmetry. As a result, we develop a molecular design criterion to predict how molecular structure affects the mechanical properties, a vital step toward integrating hybrid molecular materials into emerging nanotechnologies.

    View details for PubMedID 28976753

  • Hyperconnected molecular glass network architectures with exceptional elastic properties NATURE COMMUNICATIONS Burg, J. A., Oliver, M. S., Frot, T. J., Sherwood, M., Lee, V., Dubois, G., Dauskardt, R. H. 2017; 8: 1019

    Abstract

    Hyperconnected network architectures can endow nanomaterials with remarkable mechanical properties that are fundamentally controlled by designing connectivity into the intrinsic molecular structure. For hybrid organic-inorganic nanomaterials, here we show that by using 1,3,5 silyl benzene precursors, the connectivity of a silicon atom within the network extends beyond its chemical coordination number, resulting in a hyperconnected network with exceptional elastic stiffness, higher than that of fully dense silica. The exceptional intrinsic stiffness of these hyperconnected glass networks is demonstrated with molecular dynamics models and these model predictions are calibrated through the synthesis and characterization of an intrinsically porous hybrid glass processed from 1,3,5(triethoxysilyl)benzene. The proposed molecular design strategy applies to any materials system wherein the mechanical properties are controlled by the underlying network connectivity.

    View details for PubMedID 29044110

  • Broadband Emission with a Massive Stokes Shift from Sulfonium Pb-Br Hybrids CHEMISTRY OF MATERIALS Smith, M. D., Watson, B. L., Dauskardt, R. H., Karunadasa, H. I. 2017; 29 (17): 7083–87
  • Screening sunscreens: protecting the biomechanical barrier function of skin from solar ultraviolet radiation damage INTERNATIONAL JOURNAL OF COSMETIC SCIENCE Berkey, C., Biniek, K., Dauskardt, R. H. 2017; 39 (3): 269-274

    View details for DOI 10.1111/ics.12370

    View details for Web of Science ID 000401730700005

  • Hyperconnected network architectures as a new route to exceptional mechanical properties Burg, J., Dauskardt, R. AMER CHEMICAL SOC. 2017
  • Reliability of polymer backsheet structures in photovoltaic modules Yuen, P., Dauskardt, R. AMER CHEMICAL SOC. 2017
  • Toughening hybrid nanocomposites with molecularly confined polymers by chemically tuning the polymer-surface interaction Wang, C., Isaacson, S., Lionti, K., Volksen, W., Magbitang, T., Dauskardt, R., Dubois, G. AMER CHEMICAL SOC. 2017
  • Combining spray and atmospheric plasma deposition of transparent bilayer protective coatings on plastics for exceptional adhesion and hardness Ding, Y., Dong, S., He, D., Zhao, Z., Dauskardt, R. AMER CHEMICAL SOC. 2017
  • Effects of network termination on elastic and thermal expansion asymmetries in hybrid molecular materials Burg, J., Dauskardt, R. AMER CHEMICAL SOC. 2017
  • Dual precursor atmospheric plasma deposition of organosilicate transparent functional coating on plastics Dong, S., Ding, Y., He, D., Zhao, Z., Dauskardt, R. AMER CHEMICAL SOC. 2017
  • An Artificial Solid Electrolyte Interphase with High Li-Ion Conductivity, Mechanical Strength, and Flexibility for Stable Lithium Metal Anodes. Advanced materials Liu, Y., Lin, D., Yuen, P. Y., Liu, K., Xie, J., Dauskardt, R. H., Cui, Y. 2017; 29 (10)

    Abstract

    An artificial solid electrolyte interphase (SEI) is demonstrated for the efficient and safe operation of a lithium metal anode. Composed of lithium-ion-conducting inorganic nanoparticles within a flexible polymer binder matrix, the rationally designed artificial SEI not only mechanically suppresses lithium dendrite formation but also promotes homogeneous lithium-ion flux, significantly enhancing the efficiency and cycle life of the lithium metal anode.

    View details for DOI 10.1002/adma.201605531

    View details for PubMedID 28032934

  • Understanding mechanical behavior and reliability of organic electronic materials MRS BULLETIN Kim, J., Lee, I., Kim, T., Rolston, N., Watson, B. L., Dauskardt, R. H. 2017; 42 (2): 115-123

    View details for DOI 10.1557/mrs.2017.3

    View details for Web of Science ID 000398471500012

  • Encapsulation and backsheet adhesion metrology for photovoltaic modules PROGRESS IN PHOTOVOLTAICS Tracy, J., Bosco, N., Novoa, F., Dauskardt, R. 2017; 25 (1): 87-96

    View details for DOI 10.1002/pip.2817

    View details for Web of Science ID 000390802400010

  • Encapsulant Adhesion to Surface Metallization on Photovoltaic Cells Tracy, J., Bosco, N., Dauskardt, R., IEEE IEEE. 2017: 3200–3203
  • Defining Threshold Values of Encapsulant and Backsheet Adhesion for PV Module Reliability Bosco, N., Eafanti, J., Kurtz, S., Tracy, J., Dauskardt, R., IEEE IEEE. 2017: 3190–94
  • Improved mechanical adhesion and electronic stability of organic solar cells with thermal ageing: the role of diffusion at the hole extraction interface JOURNAL OF MATERIALS CHEMISTRY A Greenbank, W., Rolston, N., Destouesse, E., Wantz, G., Hirsch, L., Dauskardt, R., Chambon, S. 2017; 5 (6): 2911-2919

    View details for DOI 10.1039/c6ta09665d

    View details for Web of Science ID 000395075600058

  • Degradation of thermally-cured silicone encapsulant under terrestrial UV SOLAR ENERGY MATERIALS AND SOLAR CELLS Cai, C., Miller, D. C., Tappan, I. A., Dauskardt, R. H. 2016; 157: 346-353
  • Mechanical integrity of solution-processed perovskite solar cells EXTREME MECHANICS LETTERS Rolston, N., Watson, B. L., Bailie, C. D., McGehee, M. D., Bastos, J. P., Gehlhaar, R., Kim, J., Vak, D., Mallajosyula, A., Gupta, G., Mohite, A. D., Dauskardt, R. H. 2016; 9: 353–58
  • Role of Carbon Bridge Length of Organosilicate Precursors on the Atmospheric Plasma Deposition of Transparent Bilayer Protective Coatings on Plastics PLASMA PROCESSES AND POLYMERS Dong, S., Han, J., Zhao, Z., Dauskardt, R. H. 2016; 13 (11): 1053-1060
  • Optical properties of metal oxynitride thin films grown with atmospheric plasma deposition JOURNAL OF PHYSICS D-APPLIED PHYSICS Hovish, M. Q., Dauskardt, R. H. 2016; 49 (39)
  • Cross-Linkable, Solvent-Resistant Fullerene Contacts for Robust and Efficient Perovskite Solar Cells with Increased J(SC) and V-OC ACS APPLIED MATERIALS & INTERFACES Watson, B. L., Rolston, N., Bush, K. A., Leijtens, T., McGehee, M. D., Dauskardt, R. H. 2016; 8 (39): 25896-25904

    Abstract

    The active layers of perovskite solar cells are also structural layers and are central to ensuring that the structural integrity of the device is maintained over its operational lifetime. Our work evaluating the fracture energies of conventional and inverted solution-processed MAPbI3 perovskite solar cells has revealed that the MAPbI3 perovskite exhibits a fracture resistance of only ∼0.5 J/m(2), while solar cells containing fullerene electron transport layers fracture at even lower values, below ∼0.25 J/m(2). To address this weakness, a novel styrene-functionalized fullerene derivative, MPMIC60, has been developed as a replacement for the fragile PC61BM and C60 transport layers. MPMIC60 can be transformed into a solvent-resistant material through curing at 250 °C. As-deposited films of MPMIC60 exhibit a marked 10-fold enhancement in fracture resistance over PC61BM and a 14-fold enhancement over C60. Conventional-geometry perovskite solar cells utilizing cured films of MPMIC60 showed a significant, 205% improvement in fracture resistance while exhibiting only a 7% drop in PCE (13.8% vs 14.8% PCE) in comparison to the C60 control, enabling larger VOC and JSC values. Inverted cells fabricated with MPMIC60 exhibited a 438% improvement in fracture resistance with only a 6% reduction in PCE (12.3% vs 13.1%) in comparison to those utilizing PC61BM, again producing a higher JSC.

    View details for DOI 10.1021/acsami.6b06164

    View details for Web of Science ID 000384951800030

    View details for PubMedID 27604192

  • . ACS applied materials & interfaces Watson, B. L., Rolston, N., Bush, K. A., Leijtens, T., McGehee, M. D., Dauskardt, R. H. 2016; 8 (39): 25896-25904

    Abstract

    The active layers of perovskite solar cells are also structural layers and are central to ensuring that the structural integrity of the device is maintained over its operational lifetime. Our work evaluating the fracture energies of conventional and inverted solution-processed MAPbI3 perovskite solar cells has revealed that the MAPbI3 perovskite exhibits a fracture resistance of only ∼0.5 J/m(2), while solar cells containing fullerene electron transport layers fracture at even lower values, below ∼0.25 J/m(2). To address this weakness, a novel styrene-functionalized fullerene derivative, MPMIC60, has been developed as a replacement for the fragile PC61BM and C60 transport layers. MPMIC60 can be transformed into a solvent-resistant material through curing at 250 °C. As-deposited films of MPMIC60 exhibit a marked 10-fold enhancement in fracture resistance over PC61BM and a 14-fold enhancement over C60. Conventional-geometry perovskite solar cells utilizing cured films of MPMIC60 showed a significant, 205% improvement in fracture resistance while exhibiting only a 7% drop in PCE (13.8% vs 14.8% PCE) in comparison to the C60 control, enabling larger VOC and JSC values. Inverted cells fabricated with MPMIC60 exhibited a 438% improvement in fracture resistance with only a 6% reduction in PCE (12.3% vs 13.1%) in comparison to those utilizing PC61BM, again producing a higher JSC.

    View details for PubMedID 27604192

  • Screening sunscreens: protecting the biomechanical barrier function of skin from solar ultraviolet radiation damage. International journal of cosmetic science Berkey, C., Biniek, K., Dauskardt, R. H. 2016

    Abstract

    Solar ultraviolet (UV) radiation is ubiquitous in human life and well known to cause skin damage that can lead to harmful conditions such as erythema. Although sunscreen is a popular form of protection for some of these conditions, it is unclear whether sunscreen can maintain the mechanical barrier properties of skin. The objective of this study was to determine whether in vitro thin-film mechanical analysis techniques adapted for biological tissue are able to characterize the efficacy of commonly used UV inhibitors and commercial sunscreens to protect the biomechanical barrier properties of stratum corneum (SC) from UV exposure.The biomechanical properties of SC samples were assayed through measurements of the SC's drying stress profile and delamination energy. The drying stresses within SC were characterized from the curvature of a borosilicate glass substrate onto which SC had been adhered. Delamination energies were characterized using a double-cantilever beam (DCB) cohesion testing method. Successive DCB specimens were prepared from previously separated specimens by adhering new substrates onto each side of the already tested specimen to probe delamination energies deeper into the SC. These properties of the SC were measured before and after UV exposure, both with and without sunscreens applied, to determine the role of sunscreen in preserving the barrier function of SC.The drying stress in SC starts increasing sooner and rises to a higher plateau stress value after UVA exposure as compared to non-UV-exposed control specimens. For specimens that had sunscreen applied, the UVA-exposed and non-UV-exposed SC had similar drying stress profiles. Additionally, specimens exposed to UVB without protection from sunscreen exhibited significantly lower delamination energies than non-UV-exposed controls. With commercial sunscreen applied, the delamination energy for UV-exposed and non-UV-exposed tissue was consistent, even up to large doses of UVB.In vitro thin-film mechanical analysis techniques can readily characterize the effects of SC's exposure to UV radiation. The methods used in this study demonstrated commercial sunscreens were able to preserve the biomechanical properties of SC during UV exposure, thus indicating the barrier function of SC was also maintained.

    View details for DOI 10.1111/ics.12370

    View details for PubMedID 27685249

  • Elastic and thermal expansion asymmetry in dense molecular materials. Nature materials Burg, J. A., Dauskardt, R. H. 2016; 15 (9): 974-980

    Abstract

    The elastic modulus and coefficient of thermal expansion are fundamental properties of elastically stiff molecular materials and are assumed to be the same (symmetric) under both tension and compression loading. We show that molecular materials can have a marked asymmetric elastic modulus and coefficient of thermal expansion that are inherently related to terminal chemical groups that limit molecular network connectivity. In compression, terminal groups sterically interact to stiffen the network, whereas in tension they interact less and disconnect the network. The existence of asymmetric elastic and thermal expansion behaviour has fundamental implications for computational approaches to molecular materials modelling and practical implications on the thermomechanical strains and associated elastic stresses. We develop a design space to control the degree of elastic asymmetry in molecular materials, a vital step towards understanding their integration into device technologies.

    View details for DOI 10.1038/nmat4674

    View details for PubMedID 27348577

  • Effect of Mechanical Constraint on Tearing Energy of Polymer Membranes MACROMOLECULAR MATERIALS AND ENGINEERING Yuen, P. Y., Dauskardt, R. H. 2016; 301 (9): 1096-1103
  • A stability study of roll-to-roll processed organic photovoltaic modules containing a polymeric electron-selective layer SOLAR ENERGY MATERIALS AND SOLAR CELLS Weerasinghe, H. C., Rolston, N., Vak, D., Scully, A. D., Dauskardt, R. H. 2016; 152: 133-140
  • Quantitative adhesion characterization of antireflective coatings in multijunction photovoltaics SOLAR ENERGY MATERIALS AND SOLAR CELLS Brock, R., Rewari, R., Novoa, F. D., Hebert, P., Ermer, J., Miller, D. C., Dauskardt, R. H. 2016; 153: 78-83
  • Organothiol-Based Hybrid-Layer Strategy for High-Performance Copper Adhesion and Stress-Migration via Simultaneous Oxide Reduction ADVANCED MATERIALS INTERFACES Xiao, Q., Watson, B. L., Dauskardt, R. H. 2016; 3 (14)
  • Role of Stress Factors on the Adhesion of Interfaces in R2R Fabricated Organic Photovoltaics ADVANCED ENERGY MATERIALS Corazza, M., Rolston, N., Dauskardt, R. H., Beliatis, M. J., Krebs, F. C., Gevorgyan, S. A. 2016; 6 (11)
  • Infiltration, imidization, and cross-linking of polyimides in molecular-scale confinement Fostvedt, J., Isaacson, S., Dauskardt, R. AMER CHEMICAL SOC. 2016
  • Controlling kinetics of heterogeneous sol-gel solution for high-performance adhesive hybrid films JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Xiao, Q., Giachino, M., Dauskardt, R. H. 2016; 77 (3): 620-626
  • Fundamental limits of material toughening in molecularly confined polymers. Nature materials Isaacson, S. G., Lionti, K., Volksen, W., Magbitang, T. P., Matsuda, Y., Dauskardt, R. H., Dubois, G. 2016; 15 (3): 294-298

    Abstract

    The exceptional mechanical properties of polymer nanocomposites are achieved through intimate mixing of the polymer and inorganic phases, which leads to spatial confinement of the polymer phase. In this study we probe the mechanical and fracture properties of polymers in the extreme limits of molecular confinement, where a stiff inorganic phase confines the polymer chains to dimensions far smaller than their bulk radius of gyration. We show that polymers confined at molecular length scales dissipate energy through a confinement-induced molecular bridging mechanism that is distinct from existing entanglement-based theories of polymer deformation and fracture. We demonstrate that the toughening is controlled by the molecular size and the degree of confinement, but is ultimately limited by the strength of individual molecules.

    View details for DOI 10.1038/nmat4475

    View details for PubMedID 26569473

  • Adhesion and debonding kinetics of photovoltaic encapsulation in moist environments PROGRESS IN PHOTOVOLTAICS Novoa, F. D., Miller, D. C., Dauskardt, R. H. 2016; 24 (2): 183-194

    View details for DOI 10.1002/pip.2657

    View details for Web of Science ID 000370324900005

  • Carbon-Bridge Incorporation in Organosilicate Coatings Using Oxidative Atmospheric Plasma Deposition. ACS applied materials & interfaces Cui, L., Dubois, G., Dauskardt, R. H. 2016; 8 (2): 1309-1318

    Abstract

    Carbon-bridges were successfully incorporated into the molecular structure of inorganic silicate films deposited onto polymer substrates using an oxidative atmospheric plasma deposition process. Key process parameters that include the precursor chemistry and delivery rate are discussed in the context of a deposition model. The resulting coating exhibited significantly improved adhesion and a 4-fold increase in moisture resistance as determined from the threshold for debonding in humid air compared to dense silica or commercial sol-gel polysiloxane coatings. Other important parameters for obtaining highly adhesive coating deposition on oxidation-sensitive polymer substrates using atmospheric plasma were also investigated to fully activate but not overoxidize the substrate. The resulting carbon molecular bridged adhesive coating showed enhanced moisture resistance, important for functional membrane applications.

    View details for DOI 10.1021/acsami.5b09971

    View details for PubMedID 26700217

  • Del1 Knockout Mice Developed More Severe Osteoarthritis Associated with Increased Susceptibility of Chondrocytes to Apoptosis. PloS one Wang, Z., Tran, M. C., Bhatia, N. J., Hsing, A. W., Chen, C., LaRussa, M. F., Fattakhov, E., Rashidi, V., Jang, K. Y., Choo, K. J., Nie, X., Mathy, J. A., Longaker, M. T., Dauskardt, R. H., Helms, J. A., Yang, G. P. 2016; 11 (8)

    Abstract

    We identified significant expression of the matricellular protein, DEL1, in hypertrophic and mature cartilage during development. We hypothesized that this tissue-specific expression indicated a biological role for DEL1 in cartilage biology.Del1 KO and WT mice had cartilage thickness evaluated by histomorphometry. Additional mice underwent medial meniscectomy to induce osteoarthritis, and were assayed at 1 week for apoptosis by TUNEL staining and at 8 weeks for histology and OA scoring. In vitro proliferation and apoptosis assays were performed on primary chondrocytes.Deletion of the Del1 gene led to decreased amounts of cartilage in the ears and knee joints in mice with otherwise normal skeletal morphology. Destabilization of the knee led to more severe OA compared to controls. In vitro, DEL1 blocked apoptosis in chondrocytes.Osteoarthritis is among the most prevalent diseases worldwide and increasing in incidence as our population ages. Initiation begins with an injury resulting in the release of inflammatory mediators. Excessive production of inflammatory mediators results in apoptosis of chondrocytes. Because of the limited ability of chondrocytes to regenerate, articular cartilage deteriorates leading to the clinical symptoms including severe pain and decreased mobility. No treatments effectively block the progression of OA. We propose that direct modulation of chondrocyte apoptosis is a key variable in the etiology of OA, and therapies aimed at preventing this important step represent a new class of regenerative medicine targets.

    View details for DOI 10.1371/journal.pone.0160684

    View details for PubMedID 27505251

  • Fracture Mechanics and Testing of Interface Adhesion Strength in Multilayered Structures - Application in Advanced Solar PV Materials and Technology Shivakumar, R., Tippabhotla, S., Handara, V., Illya, G., Tay, A. O., Novoa, F., Dauskardt, R. H., Budiman, A., Budiman, A. S., Tay, A., Caldwell, A., Aberle, A., Dauskardt, R. ELSEVIER SCIENCE BV. 2016: 47–55
  • Dual Precursor Atmospheric Plasma Deposition of Bilayer Organosilicate Protective Coatings on Plastics Dong, S., Zhao, Z., Dauskardt, R., IEEE IEEE. 2016: 192–94
  • Spray Deposition of Compositionally Graded Hybrid Layers for High-Performance Adhesion Ding, Y., Dauskardt, R. H., IEEE IEEE. 2016: 195–97
  • Transforming the P4 Process to Enhance Mechanical and Fracture Properties of ULKs Isaacson, S. G., Wang, C., Lionti, K., Volksen, W., Magbitang, T. P., Dauskardt, R. H., Dubois, G., IEEE IEEE. 2016: 150–52
  • Thermomechanical Asymmetries in ULK Dielectric Glasses Burg, J. A., Dauskardt, R. H., IEEE IEEE. 2016: 95–97
  • Development and First Results of the Width-Tapered Beam Method for Adhesion Testing of Photovoltaic Material Systems Bosco, N., Tracy, J., Dauskardt, R., Kurtz, S., IEEE IEEE. 2016: 106–10
  • Adhesion of Antireflective Coatings in Multijunction Photovoltaics Brock, R., Miller, D. C., Dauskardt, R. H., IEEE IEEE. 2016: 850–53
  • Degradation of Silicone Encapsulants in CPV Optics Cai, C., Miller, D. C., Tappan, I. A., Dauskardt, R. H., IEEE IEEE. 2016: 196–99
  • Thermal cycling effect on mechanical integrity of inverted polymer solar cells SOLAR ENERGY MATERIALS AND SOLAR CELLS Balcaen, V., Rolston, N., Dupont, S. R., Voroshazi, E., Dauskardt, R. H. 2015; 143: 418-423
  • Selective Deposition of Compositionally Graded Hybrid Adhesive Films ADVANCED MATERIALS INTERFACES Giachino, M., Watson, B. L., Dubois, G., Dauskardt, R. H. 2015; 2 (17)
  • Understanding age-induced alterations to the biomechanical barrier function of human stratum corneum JOURNAL OF DERMATOLOGICAL SCIENCE Biniek, K., Kaczyinsky, J., Matts, P., Dauskardt, R. H. 2015; 80 (2): 94-101

    Abstract

    The appearance and function of human skin are dramatically altered with aging, resulting in higher rates of severe xerosis and other skin complaints. The outermost layer of the epidermis, the stratum corneum (SC), is responsible for the biomechanical barrier function of skin and is also adversely transformed with age. With age the keratin filaments within the corneocytes are prone to crosslinking, the amount of intercellular lipids decreases resulting in fewer lipid bilayers, and the rate of corneocyte turnover decreases.The effect of these structural changes on the mechanical properties of the SC has not been determined. Here we determine how several aspects of the SC's mechanical properties are dramatically degraded with age.We performed a range of biomechanical experiments, including micro-tension, bulge, double cantilever beam, and substrate curvature testing on abdominal stratum corneum from cadaveric female donors ranging in age from 29 to 93 years old.We found that the SC stiffens with age, indicating that the keratin fibers stiffen, similarly to collagen fibers in the dermis. The cellular cohesion also increases with age, a result of the altered intercellular lipid structure. The kinetics of water movement through the SC is also decreased.Our results indicate that the combination of structural and mechanical property changes that occur with age are quite significant and may contribute to the prevalence of skin disorders among the elderly.

    View details for DOI 10.1016/j.jdermsci.2015.07.016

    View details for Web of Science ID 000366882400003

  • Understanding age-induced alterations to the biomechanical barrier function of human stratum corneum. Journal of dermatological science Biniek, K., Kaczvinsky, J., Matts, P., Dauskardt, R. H. 2015; 80 (2): 94-101

    Abstract

    The appearance and function of human skin are dramatically altered with aging, resulting in higher rates of severe xerosis and other skin complaints. The outermost layer of the epidermis, the stratum corneum (SC), is responsible for the biomechanical barrier function of skin and is also adversely transformed with age. With age the keratin filaments within the corneocytes are prone to crosslinking, the amount of intercellular lipids decreases resulting in fewer lipid bilayers, and the rate of corneocyte turnover decreases.The effect of these structural changes on the mechanical properties of the SC has not been determined. Here we determine how several aspects of the SC's mechanical properties are dramatically degraded with age.We performed a range of biomechanical experiments, including micro-tension, bulge, double cantilever beam, and substrate curvature testing on abdominal stratum corneum from cadaveric female donors ranging in age from 29 to 93 years old.We found that the SC stiffens with age, indicating that the keratin fibers stiffen, similarly to collagen fibers in the dermis. The cellular cohesion also increases with age, a result of the altered intercellular lipid structure. The kinetics of water movement through the SC is also decreased.Our results indicate that the combination of structural and mechanical property changes that occur with age are quite significant and may contribute to the prevalence of skin disorders among the elderly.

    View details for DOI 10.1016/j.jdermsci.2015.07.016

    View details for PubMedID 26276440

  • Nanoscale Interfacial Engineering for Flexible Barrier Films NANO LETTERS Cai, C., Dauskardt, R. H. 2015; 15 (10): 6751-6755

    Abstract

    Alternating layers of organic and oxide thin films used as diffusion barriers in emerging flexible device technologies are vulnerable to degradation under the influence of mechanical stresses, temperature cycling, photodegradation, and chemically active environmental species. Delamination of the internal organic to oxide interfaces often limits the operational lifetime of the barrier system. We demonstrate a method for increasing the adhesion of organic and oxide thin films by generating nanostructures at the interface. We show that the adhesion of an acrylate to silicon oxide model system can be increased by up to an order of magnitude (from ∼2 J/m(2) to 24 J/m(2)). By altering the diameter and depth of the patterns in the model systems, the adhesion energy can be changed, and the delamination pathway can be controlled. In addition, we show that a patterned interface maintains a higher adhesion than its planar counterpart for all durations of UV-A and UV-B exposure.

    View details for DOI 10.1021/acs.nanolett.5b02597

    View details for Web of Science ID 000363003100070

    View details for PubMedID 26339781

  • Dual Precursor Atmospheric Plasma Deposition of Transparent Bilayer Protective Coatings on Plastics. ACS applied materials & interfaces Dong, S., Zhao, Z., Dauskardt, R. H. 2015; 7 (32): 17929-17934

    Abstract

    We demonstrate a dual organic and inorganic precursor method to deposit transparent organosilicate protective bilayer coatings on poly methyl methacrylate (PMMA) substrates with atmospheric plasma deposition in ambient air. The bottom layer was a hybrid organosilicate adhesive layer deposited with dual organic 1,5-cyclooctadiene (CYC) and widely used inorganic tetraethoxysiline (TEOS) precursors. The selection of the organic CYC precursor allowed incorporation of a carbon chain in the organosilicate adhesive layer, which resulted in improved adhesion. The top layer was a dense silica coating with high Young's modulus and hardness deposited with TEOS. The deposited bilayer structure showed ∼100% transparency in the visible light wavelength region, twice the adhesion energy, and five times the Young's modulus of commercial polysiloxane sol-gel coatings.

    View details for DOI 10.1021/acsami.5b04622

    View details for PubMedID 26192812

  • Dual Precursor Atmospheric Plasma Deposition of Transparent Bilayer Protective Coatings on Plastics ACS APPLIED MATERIALS & INTERFACES Dong, S., Zhao, Z., Dauskardt, R. H. 2015; 7 (32): 17929-17934

    Abstract

    We demonstrate a dual organic and inorganic precursor method to deposit transparent organosilicate protective bilayer coatings on poly methyl methacrylate (PMMA) substrates with atmospheric plasma deposition in ambient air. The bottom layer was a hybrid organosilicate adhesive layer deposited with dual organic 1,5-cyclooctadiene (CYC) and widely used inorganic tetraethoxysiline (TEOS) precursors. The selection of the organic CYC precursor allowed incorporation of a carbon chain in the organosilicate adhesive layer, which resulted in improved adhesion. The top layer was a dense silica coating with high Young's modulus and hardness deposited with TEOS. The deposited bilayer structure showed ∼100% transparency in the visible light wavelength region, twice the adhesion energy, and five times the Young's modulus of commercial polysiloxane sol-gel coatings.

    View details for DOI 10.1021/acsami.5b04622

    View details for Web of Science ID 000360027100048

  • Entanglements in P3HT and their influence on thin-film mechanical properties: Insights from molecular dynamics simulations JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS Tummala, N. R., Risko, C., Bruner, C., Dauskardt, R. H., Bredas, J. 2015; 53 (13): 934-942

    View details for DOI 10.1002/polb.23722

    View details for Web of Science ID 000354821300006

  • Molecular-Scale Understanding of Cohesion and Fracture in P3HT:Fullerene Blends ACS APPLIED MATERIALS & INTERFACES Tummala, N. R., Bruner, C., Risko, C., Bredas, J., Dauskardt, R. H. 2015; 7 (18): 9957-9964

    Abstract

    Quantifying cohesion and understanding fracture phenomena in thin-film electronic devices are necessary for improved materials design and processing criteria. For organic photovoltaics (OPVs), the cohesion of the photoactive layer portends its mechanical flexibility, reliability, and lifetime. Here, the molecular mechanism for the initiation of cohesive failure in bulk heterojunction (BHJ) OPV active layers derived from the semiconducting polymer poly(3-hexylthiophene) [P3HT] and two monosubstituted fullerenes is examined experimentally and through molecular-dynamics simulations. The results detail how, under identical conditions, cohesion significantly changes due to minor variations in the fullerene adduct functionality, an important materials consideration that needs to be taken into account across fields where soluble fullerene derivatives are used.

    View details for DOI 10.1021/acsami.5b02202

    View details for Web of Science ID 000354906500074

    View details for PubMedID 25895745

  • Molecular Design for Moisture Insensitivity of Compositionally Graded Hybrid Films ACS APPLIED MATERIALS & INTERFACES Giachino, M., Dubois, G., Dauskardt, R. H. 2015; 7 (12): 6812-6818

    Abstract

    Effective bonding of organic/inorganic interfaces especially in high humidity environments is paramount to the structural reliability of modern multilayer device technologies, such as flexible electronics, photovoltaics, microelectronic devices, and fiber-metal laminates used in aerospace applications. We demonstrate the ability to design compositionally graded hybrid organic/inorganic films with an inorganic zirconium network capable of forming a moisture-insensitive bond at the interface between an oxide and organic material. By controlling the chemistry of the deposited films and utilizing time-dependent debonding studies, we were able to correlate the behavior of the hybrid films at high humidity to their underlying molecular structure. As a result, an outstanding threefold improvement in adhesion of silicon/epoxy interfaces can be obtained with the introduction of these films even in high humidity environments.

    View details for DOI 10.1021/acsami.5b00344

    View details for Web of Science ID 000352246700054

    View details for PubMedID 25751764

  • A catalytic alloy approach for graphene on epitaxial SiC on silicon wafers JOURNAL OF MATERIALS RESEARCH Iacopi, F., Mishra, N., Cunning, B. V., Goding, D., Dimitrijev, S., Brock, R., Dauskardt, R. H., Wood, B., Boeckl, J. 2015; 30 (5): 609-616

    View details for DOI 10.1557/jmr.2015.3

    View details for Web of Science ID 000351444200002

  • The relationship between water loss, mechanical stress, and molecular structure of human stratum corneum ex vivo JOURNAL OF BIOPHOTONICS Vyumvuhore, R., Tfayli, A., Biniek, K., Duplan, H., Delalleau, A., Manfait, M., Dauskardt, R., Baillet-Guffroy, A. 2015; 8 (3): 217-225

    Abstract

    Proper hydration of the stratum corneum (SC) is important for maintaining skin's vital functions. Water loss causes development of drying stresses, which can be perceived as 'tightness', and plays an important role in dry skin damage processes. However, molecular structure modifications arising from water loss and the subsequent development of stress has not been established. We investigated the drying stress mechanism by studying, ex vivo, the behaviors of the SC components during water desorption from initially fully hydrated samples using Raman spectroscopy. Simultaneously, we measure the SC mechanical stress with a substrate curvature instrument. Very good correlations of water loss to the mechanical stress of the stratum corneum were obtained, and the latter was found to depend mainly on the unbound water fraction. In addition to that, the water loss is accompanied with an increase of lipids matrix compactness characterized by lower chain freedom, while protein structure showed an increase in amount of α-helices, a decline in α-sheets, and an increase in folding in the tertiary structure of keratin. The drying process of SC involves a complex interplay of water binding, molecular modifications, and mechanical stress. This article provides a better understanding of the molecular mechanism associated to SC mechanics.

    View details for DOI 10.1002/jbio.201300169

    View details for Web of Science ID 000350452700004

    View details for PubMedID 24446389

  • Biomechanics of the barrier function of human stratum corneum Dauskardt, R. H. WILEY-BLACKWELL. 2015: 141
  • Morphology and interdiffusion control to improve adhesion and cohesion properties in inverted polymer solar cells SOLAR ENERGY MATERIALS AND SOLAR CELLS Dupont, S. R., Voroshazi, E., Nordlund, D., Dauskardt, R. H. 2015; 132: 443-449
  • Low-Cost, Single-Step Hybrid Bond/Barrier Films for Cu Bondlines in Advanced Packaging Xiao, Q., Watson, B., Dauskardt, R. H., IEEE IEEE. 2015: 225–27
  • Decohesion Kinetics in Polymer Organic Solar Cells ACS APPLIED MATERIALS & INTERFACES Bruner, C., Novoa, F., Dupont, S., Dauskardt, R. 2014; 6 (23): 21474-21483

    Abstract

    We investigate the role of molecular weight (MW) of the photoactive polymer poly(3-hexylthiophene) (P3HT) on the temperature-dependent decohesion kinetics of bulk heterojunction (BHJ) organic solar cells (OSCs). The MW of P3HT has been directly correlated to its carrier field effect mobilities and the ambient temperature also affects OSC in-service performance and P3HT arrangement within the BHJ layer. Under inert conditions, time-dependent decohesion readily occurs within the BHJ layer at loads well below its fracture resistance. We observe that by increasing the MW of P3HT, greater resistance to decohesion is achieved. However, failure consistently occurs within the BHJ layer representing the weakest layer within the device stack. Additionally, it was found that at temperatures below the glass transition temperature (∼41-45 °C), decohesion was characterized by brittle failure via molecular bond rupture. Above the glass transition temperature, decohesion growth occurred by a viscoelastic process in the BHJ layer, leading to a significant degree of viscoelastic deformation. We develop a viscoelastic model based on molecular relaxation to describe the resulting behavior. The study has implications for OSC long-term reliability and device performance, which are important for OSC production and implementation.

    View details for DOI 10.1021/am506482q

    View details for Web of Science ID 000346326600107

    View details for PubMedID 25369109

  • Loss of Keratinocyte Focal Adhesion Kinase Stimulates Dermal Proteolysis Through Upregulation of MMP9 in Wound Healing ANNALS OF SURGERY Wong, V. W., Garg, R. K., Sorkin, M., Rustad, K. C., Akaishi, S., Levi, K., Nelson, E. R., Tran, M., Rennert, R., Liu, W., Longaker, M. T., Dauskardt, R. H., Gurtner, G. C. 2014; 260 (6): 1138-1146

    Abstract

    To investigate how epithelial mechanotransduction pathways impact wound repair.Mechanical forces are increasingly recognized to influence tissue repair, but their role in chronic wound pathophysiology remains unknown. Studies have shown that chronic wounds exhibit high levels of matrix metalloproteinase 9 (MMP9), a key proteolytic enzyme that regulates wound remodeling. We hypothesized that epithelial mechanosensory pathways regulated by keratinocyte-specific focal adhesion kinase (FAK) control dermal remodeling via MMP9.A standard wound model was applied to keratinocyte-specific FAK knockout (KO) and control mice. Rates of wound healing were measured and tissue was obtained for histologic and molecular analyses. Transcriptional and immunoblot assays were used to assess the activation of FAK, intracellular kinases, and MMP9 in vitro. A cell suspension model was designed to validate the importance of FAK mechanosensing, p38, and MMP9 secretion in human cells. Biomechanical testing was utilized to evaluate matrix tensile properties in FAK KO and control wounds.Wound healing in FAK KO mice was significantly delayed compared with controls (closure at 15 days compared with 20 days, P = 0.0003). FAK KO wounds demonstrated decreased dermal thickness and collagen density. FAK KO keratinocytes exhibited overactive p38 and MMP9 signaling in vitro, findings recapitulated in human keratinocytes via the deactivation of FAK in the cell suspension model. Functionally, FAK KO wounds were significantly weaker and more brittle than control wounds, results consistent with the histologic and molecular analyses.Keratinocyte FAK is highly responsive to mechanical cues and may play a critical role in matrix remodeling via regulation of p38 and MMP9. These findings suggest that aberrant epithelial mechanosensory pathways may contribute to pathologic dermal proteolysis and wound chronicity.

    View details for DOI 10.1097/SLA.0000000000000219

    View details for Web of Science ID 000345217200030

  • Loss of keratinocyte focal adhesion kinase stimulates dermal proteolysis through upregulation of MMP9 in wound healing. Annals of surgery Wong, V. W., Garg, R. K., Sorkin, M., Rustad, K. C., Akaishi, S., Levi, K., Nelson, E. R., Tran, M., Rennert, R., Liu, W., Longaker, M. T., Dauskardt, R. H., Gurtner, G. C. 2014; 260 (6): 1138-1146

    Abstract

    To investigate how epithelial mechanotransduction pathways impact wound repair.Mechanical forces are increasingly recognized to influence tissue repair, but their role in chronic wound pathophysiology remains unknown. Studies have shown that chronic wounds exhibit high levels of matrix metalloproteinase 9 (MMP9), a key proteolytic enzyme that regulates wound remodeling. We hypothesized that epithelial mechanosensory pathways regulated by keratinocyte-specific focal adhesion kinase (FAK) control dermal remodeling via MMP9.A standard wound model was applied to keratinocyte-specific FAK knockout (KO) and control mice. Rates of wound healing were measured and tissue was obtained for histologic and molecular analyses. Transcriptional and immunoblot assays were used to assess the activation of FAK, intracellular kinases, and MMP9 in vitro. A cell suspension model was designed to validate the importance of FAK mechanosensing, p38, and MMP9 secretion in human cells. Biomechanical testing was utilized to evaluate matrix tensile properties in FAK KO and control wounds.Wound healing in FAK KO mice was significantly delayed compared with controls (closure at 15 days compared with 20 days, P = 0.0003). FAK KO wounds demonstrated decreased dermal thickness and collagen density. FAK KO keratinocytes exhibited overactive p38 and MMP9 signaling in vitro, findings recapitulated in human keratinocytes via the deactivation of FAK in the cell suspension model. Functionally, FAK KO wounds were significantly weaker and more brittle than control wounds, results consistent with the histologic and molecular analyses.Keratinocyte FAK is highly responsive to mechanical cues and may play a critical role in matrix remodeling via regulation of p38 and MMP9. These findings suggest that aberrant epithelial mechanosensory pathways may contribute to pathologic dermal proteolysis and wound chronicity.

    View details for DOI 10.1097/SLA.0000000000000219

    View details for PubMedID 25389925

  • Controlling Interdiffusion, Interfacial Composition, and Adhesion in Polymer Solar Cells ADVANCED MATERIALS INTERFACES Dupont, S. R., Voroshazi, E., Nordlund, D., Vandewal, K., Dauskardt, R. H. 2014; 1 (7)
  • Highly Transparent Multifunctional Bilayer Coatings on Polymers Using Low-Temperature Atmospheric Plasma Deposition ACS NANO Cui, L., Lionti, K., Ranade, A., Larson-Smith, K., Dubois, G. J., Dauskardt, R. H. 2014; 8 (7): 7186-7191

    Abstract

    We report on the synthesis of hard, adhesive, and highly transparent bilayer organosilicate thin films on large poly(methyl methacrylate) substrates by atmospheric plasma, in ambient air, at room temperature, in a one-step process, using a single precursor. The method overcomes the challenge of fabricating coatings with high mechanical and interfacial properties in a one-step process. The bottom layer is a carbon-bridged hybrid silica with excellent adhesion with the poly(methyl methacrylate) substrate, and the top layer is a dense silica with high Young’s modulus, hardness, and scratch resistance. The bilayer structure exhibited ~100% transmittance in the visible wavelength range, twice the adhesion energy and three times the Young’s modulus of commercial polysiloxane sol–gel coatings.

    View details for DOI 10.1021/nn502161p

    View details for Web of Science ID 000339463100075

    View details for PubMedID 24987933

  • Conductive Transparent TiNx/TiO2 Hybrid Films Deposited on Plastics in Air Using Atmospheric Plasma Processing ADVANCED FUNCTIONAL MATERIALS Dong, S., Watanabe, M., Dauskardt, R. H. 2014; 24 (20): 3075-3081
  • Interface Structure of Cu Wire Bonding on Cu Substrate with Sn Plating JOURNAL OF THE JAPAN INSTITUTE OF METALS Fujiwara, S., Dauskardt, R. H. 2014; 78 (5): 177–82
  • Identifying the biomechanical effects of UV resistant nanoparticles on human skin Nainar, S. J., Biniek, K., Dauskardt, R. AMER CHEMICAL SOC. 2014
  • Atmospheric plasma deposition of transparent semiconducting ZnO films on plastics in ambient air ORGANIC ELECTRONICS Watanabe, M., Cui, L., Dauskardt, R. H. 2014; 15 (3): 775-784
  • Abstract 33: Stress Offloading through Mechanomodulation is Associated with Down-Regulation of Inflammatory Pathways in a Large Animal Model. Plastic and reconstructive surgery Januszyk, M., Wong, V. W., Bhatt, K., Vial, I. N., Dauskardt, R., Longaker, M. T., Gurtner, G. C. 2014; 133 (3): 44-?

    View details for DOI 10.1097/01.prs.0000445066.09978.3b

    View details for PubMedID 25942144

  • Decohesion Kinetics of PEDOT: PSS Conducting Polymer Films ADVANCED FUNCTIONAL MATERIALS Dupont, S. R., Novoa, F., Voroshazi, E., Dauskardt, R. H. 2014; 24 (9): 1325-1332
  • Role of Molecular Weight on the Mechanical Device Properties of Organic Polymer Solar Cells MACROMOLECULES Bruner, C., Dauskardt, R. 2014; 47 (3): 1117-1121

    View details for DOI 10.1021/ma402215j

    View details for Web of Science ID 000331344200029

  • Toughening Thin-Film Structures with Ceramic-Like Amorphous Silicon Carbide Films SMALL Matsuda, Y., Ryu, I., King, S. W., Bielefeld, J., Dauskardt, R. H. 2014; 10 (2): 253-257

    Abstract

    A significant improvement of adhesion in thin-film structures is demonstrated using embedded ceramic-like amorphous silicon carbide films (a-SiC:H films). a-SiC:H films exhibit plasticity at the nanoscale and outstanding chemical and thermal stability unlike most materials. The multi-functionality and the ease of processing of the films have potential to offer a new toughening strategy for reliability of nanoscale device structures.

    View details for Web of Science ID 000331112100004

    View details for PubMedID 23894055

  • An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film. Nature communications Pan, L., Chortos, A., Yu, G., Wang, Y., Isaacson, S., Allen, R., Shi, Y., Dauskardt, R., Bao, Z. 2014; 5: 3002-?

    Abstract

    Pressure sensing is an important function of electronic skin devices. The development of pressure sensors that can mimic and surpass the subtle pressure sensing properties of natural skin requires the rational design of materials and devices. Here we present an ultra-sensitive resistive pressure sensor based on an elastic, microstructured conducting polymer thin film. The elastic microstructured film is prepared from a polypyrrole hydrogel using a multiphase reaction that produced a hollow-sphere microstructure that endows polypyrrole with structure-derived elasticity and a low effective elastic modulus. The contact area between the microstructured thin film and the electrodes increases with the application of pressure, enabling the device to detect low pressures with ultra-high sensitivity. Our pressure sensor based on an elastic microstructured thin film enables the detection of pressures of less than 1Pa and exhibits a short response time, good reproducibility, excellent cycling stability and temperature-stable sensing.

    View details for DOI 10.1038/ncomms4002

    View details for PubMedID 24389734

  • Environmental mechanisms of debonding in photovoltaic backsheets SOLAR ENERGY MATERIALS AND SOLAR CELLS Novoa, F. D., Miller, D. C., Dauskardt, R. H. 2014; 120: 87-93
  • Highly Compressed Nano-Layers in Epitaxial Silicon Carbide Membranes for MEMs Sensors Brock, R. E., Iacopi, F., Iacopi, A., Hold, L., Dauskardt, R. H., IEEE IEEE. 2014: 241–43
  • Moisture-Assisted Failure Mechanisms in Underfill Epoxy/Silicon Systems for Microelectronic Packaging Giachino, M., Paredes, F., Ananthakrishnan, N., Liff, S. M., Dauskardt, R. H., IEEE IEEE. 2014: 359–61
  • An ultra-sensitive resistive pressure sensor based on hollow-sphere microstructure induced elasticity in conducting polymer film. Nature communications Pan, L., Chortos, A., Yu, G., Wang, Y., Isaacson, S., Allen, R., Shi, Y., Dauskardt, R., Bao, Z. 2014; 5: 3002-?

    Abstract

    Pressure sensing is an important function of electronic skin devices. The development of pressure sensors that can mimic and surpass the subtle pressure sensing properties of natural skin requires the rational design of materials and devices. Here we present an ultra-sensitive resistive pressure sensor based on an elastic, microstructured conducting polymer thin film. The elastic microstructured film is prepared from a polypyrrole hydrogel using a multiphase reaction that produced a hollow-sphere microstructure that endows polypyrrole with structure-derived elasticity and a low effective elastic modulus. The contact area between the microstructured thin film and the electrodes increases with the application of pressure, enabling the device to detect low pressures with ultra-high sensitivity. Our pressure sensor based on an elastic microstructured thin film enables the detection of pressures of less than 1Pa and exhibits a short response time, good reproducibility, excellent cycling stability and temperature-stable sensing.

    View details for DOI 10.1038/ncomms4002

    View details for PubMedID 24389734

  • Hybrid coupling layers for bulk metallic glass adhesion JOURNAL OF MATERIALS RESEARCH Yang, J., Dauskardt, R. H. 2013; 28 (22): 3164-3169
  • Independent Control of Adhesive and Bulk Properties of Hybrid Silica Coatings on Polycarbonate ACS APPLIED MATERIALS & INTERFACES Lionti, K., Cui, L., Volksen, W., Dauskardt, R., Dubois, G., Toury, B. 2013; 5 (21): 11276-11280

    Abstract

    Transparent polymers are widely used in many applications ranging from automotive windows to microelectronics packaging. However, their intrinsic characteristics, in particular their mechanical properties, are significantly degraded with exposure to different weather conditions. For instance, under humid environment or UV-irradiation, polycarbonate (PC) undergoes depolymerization, leading to the release of Bisphenol A, a molecule presumed to be a hormonal disruptor, potentially causing health problems. This is a serious concern and the new REACH (Registration, Evaluation, Authorization and Restriction of Chemical substances ) program dictates that materials releasing Bisphenol A should be removed from the market by January 1st, 2015 (2012-1442 law). Manufacturers have tried to satisfy this new regulation by depositing atop the PC a dense oxide-like protective coating that would act as a barrier layer. While high hardness, modulus, and density can be achieved by this approach, these coatings suffer from poor adhesion to the PC as evidenced by the numerous delamination events occurring under low scratch constraints. Here, we show that the combination of a N2/H2-plasma treatment of PC before depositing a hybrid organic-inorganic solution leads to a coating displaying elevated hardness, modulus, and density, along with a very high adherence to PC (> 20 J/m(2) as measured by double cantilever beam test). In this study, the sol-gel coatings were composed of hybrid O/I silica (based on organoalkoxysilanes and colloidal silica) and designed to favor covalent bonding between the hybrid network and the surface treated PC, hence increasing the contribution of the plastic deformation from the substrate. Interestingly, double-cantilever beam (DCB) tests showed that the coating's adhesion to PC was the same irrespective of the organoalkoxysilanes/colloidal silica ratio. The versatility of the sol-gel deposition techniques (dip-coating, spray-coating, etc.), together with the excellent mechanical properties and exceptional adherence of this hybrid material to PC should lead to interesting new applications in diverse fields: optical eye-glasses, medical materials, packaging, and so forth.

    View details for DOI 10.1021/am403506k

    View details for Web of Science ID 000327103500114

    View details for PubMedID 24090249

  • Influence of network bond percolation on the thermal, mechanical, electrical and optical properties of high and low-k a-SiC:H thin films JOURNAL OF NON-CRYSTALLINE SOLIDS King, S. W., Bielefeld, J., Xu, G., Lanford, W. A., Matsuda, Y., Dauskardt, R. H., Kim, N., Hondongwa, D., Olasov, L., Daly, B., Stan, G., Liu, M., Dutta, D., Gidley, D. 2013; 379: 67-79
  • Heterogeneous solution deposition of high-performance adhesive hybrid films. ACS applied materials & interfaces Giachino, M., Dubois, G., Dauskardt, R. H. 2013; 5 (20): 9891-9895

    Abstract

    Interfaces between organic and inorganic materials are of critical importance to the lifetime of devices found in microelectronic chips, organic electronics, photovoltaics, and high-performance laminates. Hybrid organic/inorganic materials synthesized through sol-gel processing are best suited to address these challenges because of the intimate mixing of both components. We demonstrate that deposition from heterogeneous sol-gel solutions leads to the unique nanolength-scale control of the through-thickness film composition and therefore the independent optimization of both the bulk and interfacial film properties. Consequently, an outstanding 3-fold improvement in the adhesive/cohesive properties of these hybrid films can be obtained from otherwise identical precursors.

    View details for DOI 10.1021/am403032v

    View details for PubMedID 24088533

  • Evidence of a highly compressed nanolayer at the epitaxial silicon carbide interface with silicon ACTA MATERIALIA Iacopi, F., Brock, R. E., Iacopi, A., Hold, L., Dauskardt, R. H. 2013; 61 (17): 6533-6540
  • Improved adhesion of dense silica coatings on polymers by atmospheric plasma pretreatment. ACS applied materials & interfaces Cui, L., Ranade, A. N., Matos, M. A., Dubois, G., Dauskardt, R. H. 2013; 5 (17): 8495-8504

    Abstract

    Oxygen atmospheric plasma was used to pretreat polycarbonate (PC) and stretched poly(methyl methacrylate) (PMMA) surfaces in order to enhance the adhesion of the dense silica coatings deposited by atmospheric plasma on the polymer substrates. The treatment time and chemical structure of the polymers were found to be important factors. For PC, a short treatment increased the adhesion energy, while longer treatment times decreased the adhesion. In contrast, plasma pretreatment monotonically decreased the adhesion of PMMA, and pristine PMMA exhibited much higher adhesion than the PC counterpart. We found that adhesion enhancement was achieved through improved chemical bonding, chain interdiffusion, and mechanical interlocking at the coating/substrate interface, after a short atmospheric plasma treatment. Decreased adhesion resulted from overoxidation and low-molecular-weight weak layer formation on the polymer surface by prolonged atmospheric plasma treatment. The dramatic differences in the behavior of PC and PMMA in relation to the plasma treatment time were due to their dissimilar resistance to atmospheric plasma exposure.

    View details for DOI 10.1021/am401921k

    View details for PubMedID 23942343

  • Tunable plasticity in amorphous silicon carbide films. ACS applied materials & interfaces Matsuda, Y., Kim, N., King, S. W., Bielefeld, J., Stebbins, J. F., Dauskardt, R. H. 2013; 5 (16): 7950-7955

    Abstract

    Plasticity plays a crucial role in the mechanical behavior of engineering materials. For instance, energy dissipation during plastic deformation is vital to the sufficient fracture resistance of engineering materials. Thus, the lack of plasticity in brittle hybrid organic-inorganic glasses (hybrid glasses) often results in a low fracture resistance and has been a significant challenge for their integration and applications. Here, we demonstrate that hydrogenated amorphous silicon carbide films, a class of hybrid glasses, can exhibit a plasticity that is even tunable by controlling their molecular structure and thereby leads to an increased and adjustable fracture resistance in the films. We decouple the plasticity contribution from the fracture resistance of the films by estimating the "work-of-fracture" using a mean-field approach, which provides some insight into a potential connection between the onset of plasticity in the films and the well-known rigidity percolation threshold.

    View details for DOI 10.1021/am402046e

    View details for PubMedID 23876200

  • Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices ADVANCED FUNCTIONAL MATERIALS Bruner, C., Miller, N. C., McGehee, M. D., Dauskardt, R. H. 2013; 23 (22): 2863-2871
  • Adhesion properties of inverted polymer solarcells: Processing and film structure parameters ORGANIC ELECTRONICS Dupont, S. R., Voroshazi, E., Heremans, P., Dauskardt, R. H. 2013; 14 (5): 1262-1270
  • A Mechanomodulatory Device to Minimize Incisional Scar Formation ADVANCES IN WOUND CARE Wong, V. W., Beasley, B., Zepeda, J., Dauskardt, R. H., Yock, P. G., Longaker, M. T., Gurtner, G. C. 2013; 2 (4): 185–94
  • A Mechanomodulatory Device to Minimize Incisional Scar Formation. Advances in wound care Wong, V. W., Beasley, B., Zepeda, J., Dauskardt, R. H., Yock, P. G., Longaker, M. T., Gurtner, G. C. 2013; 2 (4): 185-194

    Abstract

    To mechanically control the wound environment and prevent cutaneous scar formation.We subjected various material substrates to biomechanical testing to investigate their ability to modulate skin behavior. Combinations of elastomeric materials, adhesives, and strain applicators were evaluated to develop topical stress-shielding devices. Noninvasive imaging modalities were utilized to characterize anatomic site-specific differences in skin biomechanical properties in humans. The devices were tested in a validated large animal model of hypertrophic scarring. Phase I within-patient controlled clinical trials were conducted to confirm their safety and efficacy in scar reduction in patients undergoing abdominoplasty surgery.Among the tested materials and device applicators, a polymer device was developed that effectively off-loaded high tension wounds and blocked pro-fibrotic pathways and excess scar formation in red Duroc swine. In humans, different anatomic sites exhibit unique biomechanical properties that may correlate with the propensity to form scars. In the clinical trial, utilization of this device significantly reduced incisional scar formation and improved scar appearance for up to 12 months compared with control incisions that underwent routine postoperative care.This is the first device that is able to precisely control the mechanical environment of incisional wounds and has been demonstrated in multiple clinical trials to significantly reduce scar formation after surgery.Mechanomodulatory strategies to control the incisional wound environment can significantly reduce pathologic scarring and fibrosis after surgery.

    View details for PubMedID 24527342

  • Tailored amorphous silicon carbide barrier dielectrics by nitrogen and oxygen doping THIN SOLID FILMS Matsuda, Y., King, S. W., Dauskardt, R. H. 2013; 531: 552-558
  • Moisture-assisted cracking and atomistic crack path meandering in oxidized hydrogenated amorphous silicon carbide films JOURNAL OF APPLIED PHYSICS Matsuda, Y., King, S. W., Oliver, M., Dauskardt, R. H. 2013; 113 (8)

    View details for DOI 10.1063/1.4792212

    View details for Web of Science ID 000315667500032

  • Tailored Amorphous Silicon Carbide Barrier Dielectrics by Nitrogen and Oxygen Doping Thin Solid Films Matsuda, Y., King, Sean, W., Dauskardt, Reinhold, H. 2013; 531: 552 – 558
  • Evidence of a highly compressed nano-layer at the epitaxial silicon carbide interface with silicon Acta Materialia Iacopi, F., Brock, R. E., Iacopi, A. V., Hold, L., Dauskardt, R. H. 2013; 61: 6533–6540
  • Can understanding the effect of solar UV radiation on skin’s biomechanical function help prevent skin damage? Expert Review of Dermatology Biniek, K., Dauskardt, Reinhold, H. 2013; 1 (8): 5-6
  • Adhesion Properties of Inverted Polymer Solar Cells: Processing and Film Structure Parameters Organic Electronics Dupont, Stephanie, R., Voroshazi, E., Heremans, P., Dauskardt, Reinhold, H. 2013; 14: 1262–1270
  • Atmospheric Plasma Deposited Dense Silica Coatings on Plastics ACS APPLIED MATERIALS & INTERFACES Cui, L., Ranade, A. N., Matos, M. A., Pingree, L. S., Frot, T. J., Dubois, G., Dauskardt, R. H. 2012; 4 (12): 6587-6598

    Abstract

    We explore the application of a high-temperature precursor delivery system for depositing high boiling point organosilicate precursors on plastics using atmospheric plasma. Dense silica coatings were deposited on stretched poly(methyl methacrylate), polycarbonate and silicon substrates from the high boiling temperature precursor, 1, 2-bis(triethoxysilyl)ethane, and from two widely used low boiling temperature precursors, tetraethoxysilane and tetramethylcyclotetrasiloxane. The coating deposition rate, molecular network structure, density, Young's modulus and adhesion to plastics exhibited a strong dependence on the precursor delivery temperature and rate, and the functionality and number of silicon atoms in the precursor molecules. The Young's modulus of the coatings ranged from 6 to 34 GPa, depending strongly on the coating density. The adhesion of the coatings to plastics was affected by both the chemical structure of the precursor and the extent of exposure of the plastic substrate to the plasma during the initial stage of deposition. The optimum combinations of Young's modulus and adhesion were achieved with the high boiling point precursor which produced coatings with high Young's modulus and good adhesion compared to commercial polysiloxane hard coatings on plastics.

    View details for DOI 10.1021/am301723d

    View details for Web of Science ID 000313149800028

    View details for PubMedID 23182218

  • Experimental study of interfacial fracture toughness in a SiN(x)/PMMA barrier film. ACS applied materials & interfaces Kim, Y., Bulusu, A., Giordano, A. J., Marder, S. R., Dauskardt, R., Graham, S. 2012; 4 (12): 6711-6719

    Abstract

    Organic/inorganic multilayer barrier films play an important role in the semihermetic packaging of organic electronic devices. With the rise in use of flexible organic electronics, there exists the potential for mechanical failure due to the loss of adhesion/cohesion when exposed to harsh environmental operating conditions. Although barrier performance has been the predominant metric for evaluating these encapsulation films, interfacial adhesion between the organic/inorganic barrier films and factors that influence their mechanical strength and reliability has received little attention. In this work, we present the interfacial fracture toughness of a model organic/inorganic multilayer barrier (SiN(x)-PMMA). Data from four point bending (FPB) tests showed that adhesive failure occurred between the SiN(x) and PMMA, and that the adhesion increased from 4.8 to 10 J/m(2) by using a variety of chemical treatments to vary the surface energy at the interface. Moreover, the adhesion strength increased to 28 J/m(2) by creating strong covalent bonds at the interface. Overall, three factors were found to have the greatest impact on the interfacial fracture toughness which were (a) increasing the polar component of the surface energy, (b) creating strong covalent bonds at the organic/inorganic interface, and (c) by increasing the plastic zone size at the crack tip by increasing the thickness of the PMMA layer.

    View details for DOI 10.1021/am301880y

    View details for PubMedID 23127918

  • Experimental Study of Interfacial Fracture Toughness in a SiNx/PMMA Barrier Film ACS APPLIED MATERIALS & INTERFACES Kim, Y., Bulusu, A., Giordano, A. J., Marder, S. R., Dauskardt, R., Graham, S. 2012; 4 (12): 6710-6718

    Abstract

    Organic/inorganic multilayer barrier films play an important role in the semihermetic packaging of organic electronic devices. With the rise in use of flexible organic electronics, there exists the potential for mechanical failure due to the loss of adhesion/cohesion when exposed to harsh environmental operating conditions. Although barrier performance has been the predominant metric for evaluating these encapsulation films, interfacial adhesion between the organic/inorganic barrier films and factors that influence their mechanical strength and reliability has received little attention. In this work, we present the interfacial fracture toughness of a model organic/inorganic multilayer barrier (SiN(x)-PMMA). Data from four point bending (FPB) tests showed that adhesive failure occurred between the SiN(x) and PMMA, and that the adhesion increased from 4.8 to 10 J/m(2) by using a variety of chemical treatments to vary the surface energy at the interface. Moreover, the adhesion strength increased to 28 J/m(2) by creating strong covalent bonds at the interface. Overall, three factors were found to have the greatest impact on the interfacial fracture toughness which were (a) increasing the polar component of the surface energy, (b) creating strong covalent bonds at the organic/inorganic interface, and (c) by increasing the plastic zone size at the crack tip by increasing the thickness of the PMMA layer.

    View details for DOI 10.1021/am301880y

    View details for Web of Science ID 000313149800043

  • Low-temperature Al-Ge bonding for 3D integration JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Crnogorac, F., Pease, F. R., Birringer, R. P., Dauskardt, R. H. 2012; 30 (6)

    View details for DOI 10.1116/1.4762844

    View details for Web of Science ID 000311667300078

  • Solar UV radiation reduces the barrier function of human skin PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Biniek, K., Levi, K., Dauskardt, R. H. 2012; 109 (42): 17111-17116

    Abstract

    The ubiquitous presence of solar UV radiation in human life is essential for vitamin D production but also leads to skin photoaging, damage, and malignancies. Photoaging and skin cancer have been extensively studied, but the effects of UV on the critical mechanical barrier function of the outermost layer of the epidermis, the stratum corneum (SC), are not understood. The SC is the first line of defense against environmental exposures like solar UV radiation, and its effects on UV targets within the SC and subsequent alterations in the mechanical properties and related barrier function are unclear. Alteration of the SC's mechanical properties can lead to severe macroscopic skin damage such as chapping and cracking and associated inflammation, infection, scarring, and abnormal desquamation. Here, we show that UV exposure has dramatic effects on cell cohesion and mechanical integrity that are related to its effects on the SC's intercellular components, including intercellular lipids and corneodesmosomes. We found that, although the keratin-controlled stiffness remained surprisingly constant with UV exposure, the intercellular strength, strain, and cohesion decreased markedly. We further show that solar UV radiation poses a double threat to skin by both increasing the biomechanical driving force for damage while simultaneously decreasing the skin's natural ability to resist, compromising the critical barrier function of the skin.

    View details for DOI 10.1073/pnas.1206851109

    View details for Web of Science ID 000310515800073

    View details for PubMedID 23027968

    View details for PubMedCentralID PMC3479513

  • Film stresses and electrode buckling in organic solar cells SOLAR ENERGY MATERIALS AND SOLAR CELLS Brand, V., Levi, K., McGehee, M. D., Dauskardt, R. H. 2012; 103: 80-85
  • Scar Zones: Region-Specific Differences in Skin Tension May Determine Incisional Scar Formation PLASTIC AND RECONSTRUCTIVE SURGERY Wong, V. W., Levi, K., Akaishi, S., Schultz, G., Dauskardt, R. H. 2012; 129 (6): 1272-1276

    View details for DOI 10.1097/PRS.0b013e31824eca79

    View details for Web of Science ID 000304648500039

    View details for PubMedID 22634644

  • Moisture-Insensitive Polycarbosilane Films with Superior Mechanical Properties ACS APPLIED MATERIALS & INTERFACES Matsuda, Y., Rathore, J. S., Interrante, L. V., Dauskardt, R. H., Dubois, G. 2012; 4 (5): 2659-2663

    Abstract

    We report cross-linked polycarbosilane (CLPCS) films with superior mechanical properties and insensitivity to moisture. CLPCS are prepared by spin-coating and thermal curing of hexylene-bridged disilacyclobutane (DSCB) rings. The resulting films are siloxane-free and hydrophobic, and present good thermal stability and a low dielectric constant of k = 2.5 without the presence of supermicropores and mesopores. The elastic stiffness and fracture resistance of the films substantially exceed those of traditional porous organosilicate glasses because of their unique molecular structure. Moreover, the films show a remarkable insensitivity to moisture attack, which cannot be achieved by traditional organosilicate glasses containing siloxane bonds. These advantages make the films promising candidates for replacing traditional organosilicate glasses currently used in numerous applications, and for use in emerging nanoscience and energy applications that need protection from moisture and harsh environments.

    View details for DOI 10.1021/am300312y

    View details for Web of Science ID 000304285200047

    View details for PubMedID 22500550

  • Cohesion and device reliability in organic bulk heterojunction photovoltaic cells SOLAR ENERGY MATERIALS AND SOLAR CELLS Brand, V., Bruner, C., Dauskardt, R. H. 2012; 99: 182-189
  • Contamination and moisture absorption effects on the mechanical properties of catalyst coated membranes in PEM fuel cells INTERNATIONAL JOURNAL OF HYDROGEN ENERGY Jia, R., Dong, S., Hasegawa, T., Ye, J., Dauskardt, R. H. 2012; 37 (8): 6790-6797
  • Environmentally assisted debonding of copper/barrier interfaces ACTA MATERIALIA Birringer, R. P., Shaviv, R., Besser, P. R., Dauskardt, R. H. 2012; 60 (5): 2219-2228
  • Interlayer adhesion in roll-to-roll processed flexible inverted polymer solar cells Conference on Global Organic Photovoltaics (GOPV) Dupont, S. R., Oliver, M., Krebs, F. C., Dauskardt, R. H. ELSEVIER SCIENCE BV. 2012: 171–175
  • Fracture properties of hydrogenated amorphous silicon carbide thin films ACTA MATERIALIA Matsuda, Y., King, S. W., BIELEFELD, J., Xu, J., Dauskardt, R. H. 2012; 60 (2): 682-691
  • Interface Structure of Cu Wire Bonding on Cu Substrate with Sn Plating MATERIALS TRANSACTIONS Fujiwara, S., Dauskardt, R. H. 2012; 53 (12): 2091–96
  • Film Stresses and Electrode Buckling in Organic Solar Cells Solar Energy Materials and Solar Cells Brand, V., Levi, K., McGehee, M., Dauskardt, Reinhold, H. 2012; 103: 80–85
  • Solar UV-Radiation Reduces the Barrier Function of Human Skin Biniek, K., Levi, K., Dauskardt, Reinhold, H. 2012
  • Moisture-Assisted Cracking and Atomistic Crack Path Meandering in Oxidized Hydrogenated Amorphous Silicon Carbide Films Journal of Applied Physics Matsuda, Y., King, Sean, W., Oliver, M., Dauskardt, Reinhold, H. 2012; 8 (113): 083521-1 - 7
  • Moisture Resistant Hybrid Layer for High-Performance Adhesion TECHCON Paredes, F., Giachino, M., Ananthakrishnan, N., Liff, Shawna, M., Dauskardt, Reinhold, H. 2012
  • Contamination and Moisture Absorption Effects on the Mechanical Properties of Catalyst Coated Membranes in PEM Fuel Cells International Journal of Hydrogen Energy Jia, R., Dong, S., Hasegawa, T., Ye, J., Dauskardt, Reinhold, H. 2012; 37: 6790 - 6797
  • Fracture Properties of Hydrogenated Amorphous Silicon Carbide Thin Films Acta Materialia Matsuda, Y., King, Sean, W., Bielefeld, J., Xu, J., Dauskardt, Reinhold, H. 2012; 60: 682–691
  • Atmospheric Plasma Deposited Dense Silica Coatings on Plastics ACS Applied Materials and Interfaces Dauskardt, R., H., Cui, L., Ranade, A., Matos, M., Pingree, L., Dubois, T. 2012; 4: 6587−6598
  • Low-Temperature Al-Ge Bonding for 3D Integration Journal of Vacuum Science and Technology B Crnogorac, F., Birringer, R., Dauskardt, R., Pease, R., F. W. 2012
  • The effect of anneal, solar irradiation and humidity on the adhesion/cohesion properties of P3HT:PCBM based inverted polymer solar cells 38th IEEE Photovoltaic Specialists Conference Dupont, Stephanie, R., Voroshazi, E., Heremans, P., Dauskardt, Reinhold, H. 2012: 3-8
  • Microprobing the Mechanical Effects of Varying Dielectric Porosity in Advanced Interconnect Structures Dauskardt, R., H., Hsing, A., Geisler, H., Ryan, V., Cheng, M., Machani, K. 2012
  • Low-Temperature Al–Ge Bonding for 3D Integration Journal of Vacuum Science and Technology Crnogoraca, F., Pease, Fabian, W., Birringer, Ryan, P., Dauskardt, Reinhold, H. 2012; 6 (30)
  • Interlayer Adhesion in Roll-To-Roll Processed Flexible Inverted Polymer Solar Cells Solar Energy Materials and Solar Cells Dupont, Stephanie, R., Oliver, M., Krebs, Frederik, C., Dauskardt, Reinhold, H. 2012; 97: 171–175
  • Environmentally Assisted Debonding of Copper / Barrier Interfaces Acta Materialia Birringer, R., Shaviv, R., Besser, P., Dauskardt, R. 2012; 60: 2219–2228
  • Contamination and Moisture Absorption in Catalyst Coated Membranes in PEM Fuel Cells International Journal of Hydrogen Energy Jia, R., Dong, S., Hasegawa, T., Ye, J., Dauskardt, Reinhold, H. 2012; 37: 6790 - 6797
  • Cohesion and Device Reliability in Organic Bulk Heterojunction Photovoltaic Cells Solar Energy Materials and Solar Cells Brand, V., Bruner, C., Dauskardt, Reinhold, H. 2012; 99: 182–189
  • An Experimental Study of Interfacial Fracture Toughness in a SiNx/PMMA Barrier Film ACS Applied Materials and Interfaces Kim, Y., Bulusu, A., Giordano, A., Marder, S., Dauskardt, R., Graham, S. 2012; 4: 6711-6719
  • The effect of anneal, solar irradiation and humidity on the adhesion/cohesion properties of P3HT:PCBM based inverted polymer solar cells 38th IEEE Photovoltaic Specialists Conference (PVSC) Dupont, S. R., Voroshazi, E., Heremans, P., Dauskardt, R. H. IEEE. 2012: 3259–3262
  • Microprobing the Mechanical Effects of Varying Dielectric Porosity in Advanced Interconnect Structures IEEE International Interconnect Technology Conference (IITC) Hsing, A., Geisler, H., Ryan, V., Cheng, M., Machani, K., Breuer, D., Lehr, M. U., Paul, J., Iacopi, F., Dauskardt, R. IEEE. 2012
  • Mechanical durability of proton exchange membranes with catalyst platinum dispersion JOURNAL OF POWER SOURCES Jia, R., Han, B., Levi, K., Hasegawa, T., Ye, J., Dauskardt, R. H. 2011; 196 (20): 8234-8240
  • Effects of barrier composition and electroplating chemistry on adhesion and voiding in copper/dielectric diffusion barrier films JOURNAL OF APPLIED PHYSICS Birringer, R. P., Shaviv, R., Geiss, R. H., Read, D. T., Dauskardt, R. H. 2011; 110 (4)

    View details for DOI 10.1063/1.3624659

    View details for Web of Science ID 000294484300139

  • High yield four-point bend thin film adhesion testing techniques ENGINEERING FRACTURE MECHANICS Birringer, R. P., Chidester, P. J., Dauskardt, R. H. 2011; 78 (12): 2390-2398
  • Improving Cutaneous Scar Formation by Controlling the Mechanical Environment Large Animal and Phase I Studies ANNALS OF SURGERY Gurtner, G. C., Dauskardt, R. H., Wong, V. W., Bhatt, K. A., Wu, K., Vial, I. N., Padois, K., Korman, J. M., Longaker, M. T. 2011; 254 (2): 217-225

    Abstract

    To test the hypothesis that the mechanical environment of cutaneous wounds can control scar formation.Mechanical forces have been recognized to modulate myriad biologic processes, but the role of physical force in scar formation remains unclear. Furthermore, the therapeutic benefits of offloading cutaneous wounds with a device have not been rigorously tested.A mechanomodulating polymer device was utilized to manipulate the mechanical environment of closed cutaneous wounds in red Duroc swine. After 8 weeks, wounds subjected to different mechanical stress states underwent immunohistochemical analysis for fibrotic markers. In a phase I clinical study, 9 human patients undergoing elective abdominal surgery were treated postoperatively with a stress-shielding polymer on one side whereas the other side was treated as standard of care. Professional photographs were taken between 8 and 12 months postsurgery and evaluated using a visual analog scale by lay and professional panels. This study is registered with ClinicalTrials.gov, number NCT00766727.Stress shielding of swine incisions reduced histologic scar area by 6- and 9-fold compared to control and elevated stress states, respectively (P < 0.01 for both) and dramatically decreased the histologic expression of profibrotic markers. Closure of high-tension wounds induced human-like scar formation in the red Duroc, a phenotype effectively mitigated with stress shielding of wounds. In the study on humans, stress shielding of abdominal incisions significantly improved scar appearance (P = 0.004) compared with within-patient controls.These results indicate that mechanical manipulation of the wound environment with a dynamic stress-shielding polymer device can significantly reduce scar formation.

    View details for DOI 10.1097/SLA.0b013e318220b159

    View details for Web of Science ID 000292908700007

    View details for PubMedID 21606834

  • BIOMECHANICS OF THE BARRIER FUNCTION OF HUMAN SKIN: PREDICTING SKIN DAMAGE AND THE EFFECTS OF COSMETIC TREATMENTS JOURNAL OF COSMETIC SCIENCE Dauskardt, R. H. 2011; 62 (4): 422-423
  • Effect of cation contamination and hydrated pressure loading on the mechanical properties of proton exchange membranes JOURNAL OF POWER SOURCES Jia, R., Han, B., Levi, K., Hasegawa, T., Ye, J., Dauskardt, R. H. 2011; 196 (8): 3803-3809
  • Adhesion and degradation of hard coatings on poly (methyl methacrylate) substrates THIN SOLID FILMS Kamer, A., Larson-Smith, K., Pingree, L. S., Dauskardt, R. H. 2011; 519 (6): 1907-1913
  • Shear Microprobing of Chip-Package Interaction in Advanced Interconnect Structures Joint Conference on IEEE International Interconnect Technology Conference / 20th European Workshop on Materials for Advanced Metallization (IITC/MAM) Hsing, A. W., Kearney, A. V., Li, L., Xue, J., BRILLHART, M., Dauskardt, R. H. IEEE. 2011
  • Effect of Cation Contamination and Hydrated Pressure Loading on the Mechanical Properties of Proton Exchange Membranes Journal of Power Sources Jia, R., Han, B., Levi, K., Hasegawa, T., Ye, J., Dauskardt, Reinhold, H. 2011; 196: 3803–3809
  • Axially Graded Index LEns as a non-tracking solar concentrator SOLAR OSA (Optics for Solar Energy) Conference Vaidya, N., Dauskardt, R., H., Solgaard, O. 2011
  • Improving Cutaneous Scar by Controlling the Mechanical Environment: Large Animal and Phase I Studies Annals of Surgery Gurtner, Geoffrey, C., Dauskardt, Reinhold, H., Wong, Victor, W., Bhatt, Kirit, A., Wu, K., Vial, Ivan, N. 2011; 2 (254): 217 – 225
  • Functionally Graded Hybrid Glass Layers for High-Performance Polymer/Silicon Adhesion 2011 TECHCON Giachino, M., Kim, T., Lui, Gillian, V., Ananthakrishnan, N., Liff, Shawna, M., Dauskardt, Reinhold, H. 2011
  • Adhesion and Degradation of Hard Coatings on Poly (methyl methacrylate) Substrates Thin Solid Films Kamer, A., Larson-Smith, K., Pingree, Liam, S. C., Dauskardt, Reinhold, H. 2011; 6 (519): 1907 - 1913
  • Effect of Glycerin on Drying Stresses in Human Stratum Corneum Journal of Dermatological Science Levi, K., Kwan, A., Rhines, Allison, S., Gorcea, M., Moore, David, J., Dauskardt, Reinhold, H. 2011; 2 (61): 129 - 131
  • New classes of ULK dielectrics with superior thermomechanical properties Advanced Metallization Conference Dauskardt, R., H., Matsuda, Y., King, Sean, W., Dubois, G., Bielefeld, J., Interrante, J. 2011
  • Shear Microprobing the Mechanical Effects Varying Dielectric Porosity in Advanced Interconnect Structures Dauskardt, R., H., Hsing, A., Geisler, H., Ryan, V., Iacopi, F., Cheng, M. 2011
  • Biomechanics of the Barrier Function of Human Stratum Corneum The Art and Science of Moisturizers Levi, K., Dauskardt, Reinhold, H. 2011
  • Scar Zones: Region-Specific Differences in Skin Tension May Determine Incisional Scar Formation Plastic and Reconstructive Surgery Wong, Victor, W., Levi, K., Akaishi, S., Schultz, G., Dauskardt, Reinhold, H. 2011; 6 (129): 1272 – 1276
  • High Yield Four-Point Bend Thin Film Adhesion Testing Techniques Engineering Fracture Mechanics Birringer, R., P., Dauskardt, R., H. 2011; 78: 2390 – 2398
  • Shear Microprobing of Chip-Package Interaction in Advanced Interconnect Structures Hsing, A., W., Kearney, A., V., Li, L., Xue, J., Brillhartand, M., Dauskardt, R., H. 2011
  • Mechanical Durability of Proton Exchange Membranes with Catalyst Platinum Dispersion Journal of Power Sources Jia, R., Han, B., Levi, K., Hasegawa, T., Ye, J., Dauskardt, Reinhold, H. 2011; 196: 8234 – 8240
  • Effects of Barrier Composition and Electroplating Chemistry on Adhesion and Voiding in Copper / Dielectric Diffusion Barrier Films Journal of Applied Physics Birringer, R., Shaviv, R., Geiss, Roy, H., Read, D., Dauskardt, R. 2011; 110: 044312
  • Future of PECVD and Spin-on ultra low-k Materials Joint Conference on IEEE International Interconnect Technology Conference / 20th European Workshop on Materials for Advanced Metallization (IITC/MAM) Volksen, W., Frot, T., Magbitang, T., Gates, S., Oliver, M., Dauskardt, R., Dubois, G. IEEE. 2011
  • Emollient molecule effects on the drying stresses in human stratum corneum BRITISH JOURNAL OF DERMATOLOGY Levi, K., Kwan, A., Rhines, A. S., Gorcea, M., Moore, D. J., Dauskardt, R. H. 2010; 163 (4): 695-703

    Abstract

    Emollient molecules are widely used in skin care formulations to improve skin sensory properties and to alleviate dry skin but little is understood regarding their effects on skin biomechanical properties.To investigate the effects of emollient molecules on drying stresses in human stratum corneum (SC) and how these stresses are related to SC components and moisture content.The substrate curvature method was used to measure the drying stresses in isolated SC following exposure to selected emollient molecules. While SC stresses measured using this method have the same biaxial in vivo stress state and moisture exchange with the environment, a limitation of the method is that moisture cannot be replenished by the underlying skin layers. This provides an opportunity to study the direct effects of emollient treatments on the moisture content and the components of the SC. Attenuated total reflectance Fourier transform infrared spectroscopy was used to determine the effects of emollient molecules on SC lipid extraction and conformation. Results Emollient molecules resulted in a complex SC drying stress profile where stresses increased rapidly to peak values and then gradually decreased to significantly lower values compared with the control. The partially occlusive treatments also penetrated into the SC where they caused extraction and changes in lipid conformation. These effects together with their effects on SC moisture content are used to rationalize the drying stress profiles.Emollient molecules have dramatic effects on SC drying stresses that are related to their effects on intercellular lipids and SC moisture content.

    View details for DOI 10.1111/j.1365-2133.2010.09937.x

    View details for Web of Science ID 000282046600007

    View details for PubMedID 20633012

  • Solution chemistry effects on cracking and damage evolution during chemical-mechanical planarization JOURNAL OF MATERIALS RESEARCH Ong, M. D., Leduc, P., McKenzie, D. W., Farjot, T., Passemard, G., Maitrejean, S., Dauskardt, R. H. 2010; 25 (10): 1904-1909
  • Molecular Origins of the Mechanical Behavior of Hybrid Glasses ADVANCED FUNCTIONAL MATERIALS Oliver, M. S., Dubois, G., Sherwood, M., Gage, D. M., Dauskardt, R. H. 2010; 20 (17): 2884-2892
  • Mechanical Fatigue of Hybrid Glasses SMALL Oliver, M. S., Dauskardt, R. H. 2010; 6 (17): 1892-1896

    View details for DOI 10.1002/smll.201000667

    View details for Web of Science ID 000282268800009

    View details for PubMedID 20690136

  • Molecular structure and fracture properties of ZrOX/Epoxysilane hybrid films JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Oliver, M. S., Blohowiak, K. Y., Dauskardt, R. H. 2010; 55 (3): 360-368
  • Bilayer metal gate electrodes with tunable work function: Adhesion and interface characterization JOURNAL OF APPLIED PHYSICS Birringer, R. P., Lu, C., Deal, M., Nishi, Y., Dauskardt, R. H. 2010; 108 (5)

    View details for DOI 10.1063/1.3466957

    View details for Web of Science ID 000282478900037

  • Drying stress and damage processes in human stratum corneum. International journal of cosmetic science Levi, K., Weber, R. J., Do, J. Q., Dauskardt, R. H. 2010; 32 (4): 276-293

    Abstract

    The drying stresses that develop in stratum corneum (SC) are crucial for its mechanical and biophysical function, its cosmetic feel and appearance, and play a central role in processes of dry skin damage. However, quantitative methods to characterize these stresses are lacking and little understanding exists regarding the effects of drying environment, chemical exposures and moisturizing treatments. We describe the application of a substrate curvature technique adapted for biological tissue to accurately characterize SC drying stresses as a function of time following environmental pre-conditioning and chemical treatment in a range of drying environments. SC stresses were observed to increase to stress levels of up to approximately 3 MPa over periods of 8 h depending on pretreatment and drying environment. A unique relationship between the SC stress and water in the drying environment was established. The effect of glycerol on lowering SC stresses and damaging surfactants on elevating SC stresses were quantified. Extensions of the method to continuous monitoring of SC stresses in response to changes in environmental moisture content and temperature are reported. Finally, a biomechanics framework to account for the SC drying stress as a mechanical driving force for dry skin damage is presented.

    View details for DOI 10.1111/j.1468-2494.2009.00557.x

    View details for PubMedID 19889042

  • Application of substrate curvature method to differentiate drying stresses in topical coatings and human stratum corneum. International journal of cosmetic science Levi, K., Dauskardt, R. H. 2010; 32 (4): 294-298

    Abstract

    Despite the extensive use of topical coatings in cosmetics, their effect on the mechanical properties of human skin and the perception of skin tightness in the form of drying stresses is not well understood. We describe the application of a recently developed substrate curvature technique to characterize stresses in drying and non-drying occlusive topical coatings. We then extend the technique to measure the combined effects of the coating applied to human stratum corneum (SC) where the overall drying stresses may have contributions from the coating, the SC and the interaction of the coating with the SC. We show how these separate contributions in the coating and SC layers can be differentiated.

    View details for DOI 10.1111/j.1468-2494.2010.00568.x

    View details for PubMedID 20384900

  • Molecular Mobility under Nanometer Scale Confinement NANO LETTERS Kim, T., Dauskardt, R. H. 2010; 10 (5): 1955-1959

    Abstract

    The mobility of organic molecules under nanoscale confinement differs greatly from that in the bulk. In this study we show that the conventional free volume dependent mobility relationship explained by the free volume theory of diffusion breaks down for diffusion of linear alkane molecules in organosilicate films with connected nanoporosity. Alkane mobility under such nanoscale confinement was observed to decrease with chain length and was lower than that reported in the bulk. While the activation energy for diffusion was similar to that in the bulk, it was found to decrease with chain length exactly opposite to the trend observed in the bulk. This suggests an increasing molecular free volume with chain length. The effects of molecular polarity and pore size on diffusion were also demonstrated. Molecular mobility was found to be suppressed with increasing molecular polarity and decreasing pore size.

    View details for DOI 10.1021/nl101169s

    View details for Web of Science ID 000277444900072

    View details for PubMedID 20392106

  • Bilayer metal gate electrodes with tunable work function: Mechanism and proposed model JOURNAL OF APPLIED PHYSICS Lu, C., Wong, G. M., Birringer, R., Dauskardt, R., Deal, M. D., Clemens, B. M., Nishi, Y. 2010; 107 (6)

    View details for DOI 10.1063/1.3326237

    View details for Web of Science ID 000276210800055

  • Effects of e-beam curing on glass structure and mechanical properties of nanoporous organosilicate thin films INTERNATIONAL JOURNAL OF MATERIALS RESEARCH Gage, D. M., Peng, L., Stebbins, J., Yim, K. S., Al-Bayati, A., Demos, A., Dauskardt, R. H. 2010; 101 (2): 228-235

    View details for DOI 10.3139/146.110275

    View details for Web of Science ID 000275653100008

  • Micromechanics and Damage Processes in Interconnect Structures 60th Electronic Components and Technology Conference Hsing, A. W., Kearney, A. V., Li, L., Xue, J., BRILLHART, M., Dauskardt, R. H. IEEE. 2010: 1303–1308
  • High Toughness and Moisture Insensitive Hydrogenated Amorphous Silicon Carbide Films for MEMS/NEMS Symposium on Chemical Sensors 9 - Chemical and Biological Sensors and Analytical Systems / Symposium on Microfabricated and Nanofabricated Systems for MEMS/NEMS 9 held during the 218th Meeting of the Electrochemical-Society (ECS) Matsuda, Y., King, S. W., Bielefeld, J., Dauskardt, R. H. ELECTROCHEMICAL SOC INC. 2010: 257–61

    View details for DOI 10.1149/1.3484129

    View details for Web of Science ID 000325342000031

  • Cohesive Toughness Of Low-k Film With Periodically Changing Elastic Modulus: Cube-Corner Indentation 11th International Workshop on Stress-Induced Phenomena in Metallization Yeap, K. B., Hangen, U., Ritz, Y., Kim, T., Dauskardt, R., Zsehech, E. AMER INST PHYSICS. 2010: 159–165
  • Solution Chemistry Effects on Cracking and Damage Evolution during Chemical Mechanical Planarization Journal of Materials Research Dauskardt, R., H., Ong, Markus, D., Leduc, P., McKenzie, Daniel, W., Farjot, T., Maitrejean, G. 2010; 10 (25): 1904 - 1909
  • Molecular Mobility in Nanoporous Organosilicate Thin Films NanoLetters Kim, T., Dauskardt, Reinhold, H. 2010; 5 (10): 1955-1959
  • Molecular Design of Ultra-Low-k Hybrid Glasses Oliver, M., Dubois, G., Dauskardt, R. 2010
  • Emollient Molecule Effects on the Drying Stresses in Human Stratum Corneum British Journal of Dermatology Levi, K., Kwan, A., Rhines, A., S., Gorcea, M., Moore, D., J., Dauskardt, R., H. 2010; 4 (163): 695 – 703
  • Optimized Adhesive Bonding to Bulk Metallic Glass Substrates SAMPE 2010 Yang, J., Oliver, M., S., Dauskardt, R., H. 2010
  • Bilayer Metal Gate Electrodes with Tunable Work Function– Mechanism and Proposed Model Journal of Applied Physics Lu, C., Wong, Gloria, M. T., Birringer, Ryan, P., Dauskardt, R., Deal, M., Clemens, Bruce, M. 2010; 107: 63710
  • Bilayer Metal Gate Electrodes with Tunable Work Function – Adhesion and Interface Characterization Journal of Applied Physics Birringer, Ryan, P., Lu, C., Deal, M., Nishi, Y., Dauskardt, Reinhold, H. 2010; 108: 53704
  • Microprobing the Mechanics of Complex Interconnect Structures Hsing, A., W., Kearney, A., V., Li, L., Xue, J., Brillhart, M., Dauskardt, R., H. 2010
  • High toughness and moisture insensitive hydrogenated amorphous silicon carbide films for MEMS/NEMS ECS Transactions Matsuda, Y., King, Sean, W., Bielefeld, J., Dauskardt, Reinhold, H. 2010; 8 (33): 257-261
  • Mechanical Properties of Hydrogenated Amorphous Silicon Carbide Thin Films Matsuda, Y., King, Sean, W., Bielefeld, J., Dauskardt, Reinhold, H. 2010
  • Molecular Structure and Fracture Properties of Hybrid Organic-Inorganic Films Journal of Sol-Gel Science and Technology Oliver, Mark, S., Blohowiak, Kay, Y., Dauskardt, Reinhold, H. 2010; 55: 360 - 368
  • Crack Growth Mechanisms in Sol-Gel Adhesive Coupling Layers SAMPE 2010 Oliver, M., S., Dauskardt, R., H. 2010
  • Effects of e-Beam Curing on Glass Structure and Mechanical Properties of Nanoporous Organosilicate Thin Films International Journal of Materials Research Dauskardt, R., H., Gage, David, M., Peng, L., Stebbins, J., Yim, K. S., Demos, A. 2010; 101: 228 - 235
  • Application of Substrate Curvature Method to Differentiate Drying Stresses in Topical Coatings and Human Stratum Corneum International Journal of Cosmetic Science Levi, K., Dauskardt, R., H. 2010: 1-5
  • Integration Challenges of Nanoporous Low Dielectric Constant Materials 47th Annual IEEE International Reliability Physics Symposium Kim, T., Dauskardt, R. H. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2009: 509–15
  • Surfactant-controlled damage evolution during chemical mechanical planarization of nanoporous films ACTA MATERIALIA Kim, T., Konno, T., Dauskardt, R. H. 2009; 57 (16): 4687-4696
  • Tailoring UV cure depth profiles for optimal mechanical properties of organosilicate thin films APPLIED PHYSICS LETTERS Kim, T., Chumakov, D., Zschech, E., Dauskardt, R. H. 2009; 95 (7)

    View details for DOI 10.1063/1.3190198

    View details for Web of Science ID 000269288300016

  • Surfactant Mobility in Nanoporous Glass Films NANO LETTERS Kim, T., Mackie, K., Zhong, Q., Peterson, M., Konno, T., Dauskardt, R. H. 2009; 9 (6): 2427-2432

    Abstract

    Polymer molecules when physically confined at nanometer length scales diffuse nonclassically and very differently depending on their molecular weight and the nature of the confinement. Long polymers that exhibit "snakelike" reptation based mobility in melts may diffuse faster in confined nanometer sized cylinders with pore diameter d approximately 15 nm, and short polymers subject to Rouse dynamics have shown signatures of reptation and slower diffusion when confined in nanoporous glass with d approximately 4 nm. However, the mobility of short polymers with radii of gyration similar to a smaller pore diameter (d < or = 2.1 nm) but with extended lengths well larger than the pore diameter has not as yet been studied. In this work, we demonstrate that those short molecules including nonionic surfactants can readily diffuse in strongly hydrophobic nanoporous glasses film with d < or = 2.1 nm. The diffusivity was found sensitive to molecular weight, hydrophilic-lipophilic balance, and molecular structure of surfactants. Remarkably, analysis of the measured diffusion coefficients reveals that short-chain surfactants exhibit signature of reptation based diffusion in the nanoscopic pore confinements. Such reptation mobility in agreement with theoretical predictions is not even observed in reptating polymer melts due to fluctuations of the entanglement pathway. The fixed pathways in the interconnected nanoporous films provide ideal nanoscale environments to explore mobility of confined molecules, and the results have implications for a number of technologies where nanoporous materials are in contact with surfactant molecules.

    View details for DOI 10.1021/nl901138p

    View details for Web of Science ID 000266969400042

    View details for PubMedID 19445484

  • Effects of thermal annealing and Si incorporation on bonding structure and fracture properties of diamond-like carbon films DIAMOND AND RELATED MATERIALS Choi, H. W., Gage, D. A., Dauskardt, R. H., Lee, K., Oh, K. H. 2009; 18 (4): 615-619
  • R&D for Solar Power ADVANCED MATERIALS & PROCESSES Khan, R., Dauskardt, R. H., Geyer, M., Pearsall, T. P., Meerfeld, D. W. 2009; 167 (1): 35-37
  • Solar Power R&D Advanced Materials and Processes Khan, M., R., Dauskardt, R., H., Geyer, M., Pearsall, T., P., Merfeld, D., W. 2009; 1 (167): 35 - 37
  • Tailoring UV Cure Depth Profiles for Optimal Mechanical Properties of Organosilicate Thin Films Applied Physics Letters Kim, T., DmytroChumakov, Reinhold, E. Z. 2009; 95: 71902
  • Drying Stress and Skin Damage in Human Stratum Corneum ,” International Journal of Cosmetic Science Levi, K., Weber, Robert, J., Do, James, Q., Dauskardt, R., H. 2009: 1-8
  • Surfactant-Controlled Damage Evolution during Chemical Mechanical Planarization of Nanoporous Films Acta Materialia Kim, T., Konno, T., Dauskardt, Reinhold, H. 2009; 57: 4687 - 4696
  • Adhesion, Cu Voiding, and Debonding Kinetics of Copper / Dielectric Diffusion Barrier Films Advanced Metallization Conference Dauskardt, R., H., Birringer, R., Shaviv, R., Mountsier, T., Reid, J., Geiss, J. 2009
  • Integration Challenges of Nanoporous Low Dielectric Constant Materials IEEE Transactions on Device and Materials Reliability Kim, T., Dauskardt, Reinhold, H. 2009; 4 (9)
  • Impact of CMP polish and pCMP Cleaning on adhesion of SiCN capping layer on PECVD-derived Porous OSG and Copper 9th International Symposium on Ultra Clean Processing of Semiconductor Surfaces (UCPSS) Gage, D. M., Thiel, A. D., Dauskardt, R. H., Haas, M. K., Matz, L. M., O'Neill, M. L., Wieder, T. M., Banerjee, G., Rao, M. B. TRANS TECH PUBLICATIONS LTD. 2009: 377–380
  • Aluminum-Germanium Eutectic Bonding for 3D Integration IEEE International Conference on 3D Systems Integration Crnogorac, F., Birringer, R., Dauskardt, R., Pease, F. IEEE. 2009: 384–388
  • Pore size scaling for enhanced fracture resistance of nanoporous polymer thin films ACTA MATERIALIA Kearney, A. V., Litteken, C. S., Mohler, C. E., Mills, M. E., Dauskardt, R. H. 2008; 56 (20): 5946-5953
  • INNOVATIONS IN SOLAR POWER ADVANCED MATERIALS & PROCESSES Khan, M. R., Merfeld, D. W., Pearsall, T. P., Geyer, M., Dauskardt, R. H. 2008; 166 (11): 45-48
  • Superior mechanical properties of dense and porous organic/inorganic hybrid thin films 14th International Sol-Gel Conference Dubois, G., Volksen, W., Magbitang, T., Sherwood, M. H., Miller, R. D., Gage, D. M., Dauskardt, R. H. SPRINGER. 2008: 187–93
  • Tuning depth profiles of organosilicate films with ultraviolet curing JOURNAL OF APPLIED PHYSICS Kim, T., Tsuji, N., Matsushita, K., Kobayashi, N., Chumakov, D., Geisler, H., Zschech, E., Dauskardt, R. H. 2008; 104 (7)

    View details for DOI 10.1063/1.2999637

    View details for Web of Science ID 000260125500113

  • Molecular-controlled fracture and release of templated nanoporous organosilicate thin films ADVANCED MATERIALS Ong, M. D., Volksen, W., Dubois, G., Lee, V., Brock, P. J., Deline, V. R., Miller, R. D., Dauskardt, R. H. 2008; 20 (16): 3159-3164
  • Effects of UV cure on glass structure and fracture properties of nanoporous carbon-doped oxide thin films JOURNAL OF APPLIED PHYSICS Gage, D. M., Stebbins, J. F., Peng, L., Cui, Z., Al-Bayati, A., MacWilliams, K. P., M'saad, H., Dauskardt, R. H. 2008; 104 (4)

    View details for DOI 10.1063/1.2968438

    View details for Web of Science ID 000259265100026

  • Fatigue damage initiation and growth from artificial defects in Zr-based metallic glass ACTA MATERIALIA Menzel, B. C., Dauskardt, R. H. 2008; 56 (13): 2955-2965
  • Depth dependence of ultraviolet curing of organosilicate low-k thin films JOURNAL OF APPLIED PHYSICS Kim, T., Tsuji, N., Kemeling, N., Matsushita, K., Chumakov, D., Geisler, H., Zschech, E., Dauskardt, R. H. 2008; 103 (6)

    View details for DOI 10.1063/1.2894727

    View details for Web of Science ID 000254536900094

  • Characteristic of silver doped DLC films on surface properties and protein adsorption DIAMOND AND RELATED MATERIALS Choi, H. W., Dauskardt, R. H., Lee, S., Lee, K., Oh, K. H. 2008; 17 (3): 252-257
  • Quantitative roadmap for optimizing CMP of ultra-low-k dielectrics IEEE International Interconnect Technology Conference Kim, T., Konno, T., Yamanaka, T., Dauskardt, R. H. IEEE. 2008: 171–173
  • Tuning Depth Profiles of Organosilicate Films with Ultraviolet Curing Journal of Applied Physics Dauskardt, R., H., Kim, T., Tsuji, N., Matsushita, K., Chumakov, D., Zschech, H. 2008; 104: 74113
  • Fatigue Damage Initiation and Growth from Artificial Defects in Zr-Based Metallic Glass Acta Materialia Menzel, B., Dauskardt, R., H. 2008; 56: 2955 – 2965
  • Innovations in Solar Power Advanced Materials and Processes Khan, M., R., Merfeld, D., W., Pearsall, T., P., Geyer, M., Dauskardt, R., H. 2008; 11 (166): 45 - 48
  • Effects of Current Density, Environments and Temperature on Adhesion and Debonding Kinetics of Cu / Barrier Interfaces Advanced Metallization Conference Birringer, R., Shaviv, R., Dauskardt, Reinhold, H. 2008: 331-336
  • Characteristic of Silver Doped DLC Films on Surface Properties and Protein Adsorption Diamond and Related Materials Choi, H., W., Dauskardt, R., H., Lee, S, C., Lee, K. R., Oh, K., H. 2008
  • Pore Size Scaling for Enhanced Fracture Resistance of Nanoporous Polymer Thin Films Acta Materialia Kearney, A., V., Litteken, C., S., Mohler, C., E., Mills, M., E., Dauskardt, R., H. 2008; 56: 5946–5953
  • Effects of UV Cure on Glass Structure and Fracture Properties of Nanoporous Carbon-Doped Oxide Thin Films Journal of Applied Physics Dauskardt, R., H., Gage, D., M., Stebbins, J., F., Peng, L., Cui, Z., MacWilliams, A. 2008; 104: 43513
  • Depth Dependence of Ultraviolet (UV) Curing of Organosilicate Low-K Films Journal of Applied Physics Kim, T., Tsuji, N., Matsushita, K., Chumakov, D., Zschech, E., Dauskardt, Reinhold, H. 2008; 103: 64108
  • Tuning Depth Profiles of Low-k Dielectrics with UV Curing Advanced Metallization Conference Dauskardt, R., H., Kim, T., Tsuji, N., Hilst, J. d., Kobayashi, K. N., Geisler, D. 2008: 337-340
  • Reliability of Adhesive Interphases for Titanium-Graphite Laminates SAMPE 2008 Oliver, Mark, S., Blohowiak, Kay, Y., Dauskardt, Reinhold, H. 2008
  • Optimizing CMP for Ultra-Low-k Dielectrics 13th International Chemical Mechanical Planarization Conference for ULSI Multilevel Interconnection Kim, T., Konno, T., Yamanaka, T., Dauskardt, Reinhold, H. 2008
  • Molecular Controlled Fracture and Release of Templated Nanoporous Organosilicate Thin Films Advanced Materials Dauskardt, R., H., Ong, M., Volksen, W., Dubois, G., Lee, V., Deline, P., J. 2008; 20: 3159–3164
  • Effect of Corneodesmosome Degradation on the Intercellular Delamination of Human Stratum Corneum Journal of Investigative Dermatology Levi, K., Baxter, J., Meldrum, H., Misra, M., Pashkovski, E., Dauskardt, R., H. 2008; 9 (128): 2345 – 2347
  • The Role of Friction and Loading Parameters on Four-Point Bend Adhesion Measurements Journal of Materials Research Gage, D., M., Kim, K., Litteken, C., S., Dauskardt, R., H. 2008; 1 (23): 87 – 96
  • UV, e-beam, and thermal curing of low-k organosilicates: Effects on glass structure and mechanical properties 24th Advanced Metallization Conference 2007 (AMC) Gage, D. M., Yim, K. S., Al-Bayati, A., Demos, A., M'saad, H., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2008: 433–438
  • Depth dependence of UV curing of organosilicate low-k thin films 24th Advanced Metallization Conference 2007 (AMC) Kim, T., Tsuji, N., van der Hilst, J., Kemeling, N., Matsushita, K., Kobayashi, N., Chumakov, D., Geisler, H., Zschech, E., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2008: 455–458
  • Role of friction and loading parameters in four-point bend adhesion measurements JOURNAL OF MATERIALS RESEARCH Gage, D. M., Kim, K., Litteken, C. S., Dauskardt, R. H. 2008; 23 (1): 87-96
  • Molecular network reinforcement of sol-gel glasses ADVANCED MATERIALS Dubois, G., Volksen, W., Magbitang, T., Miller, R. D., Gage, D. M., Dauskardt, R. H. 2007; 19 (22): 3989-?
  • Time-dependant intercellular delamination of human stratum corneum JOURNAL OF MATERIALS SCIENCE Wu, K. S., Li, J., Ananthapadmanabhan, K. P., Dauskardt, R. H. 2007; 42 (21): 8986-8994
  • Response to comments on "The fatigue endurance limit of a Zr-based bulk metallic glass" SCRIPTA MATERIALIA Menzel, B. C., Dauskardt, R. H. 2007; 57 (1): 69-71
  • Adhesion between template materials and UV-cured nanoimprint resists JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B Houle, F. A., Guyer, E., Miller, D. C., Dauskardt, R. 2007; 25 (4): 1179-1185

    View details for DOI 10.1116/1.2746336

    View details for Web of Science ID 000249170100015

  • Anomalous debonding behavior of a polymer/inorganic interface ACTA MATERIALIA Sharratt, B. M., Wang, L. C., Dauskardt, R. H. 2007; 55 (10): 3601-3609
  • Aqueous solution diffusion in hydrophobic nanoporous thin-film glasses JOURNAL OF MATERIALS RESEARCH Guyer, E. P., Gantz, J., Dauskardt, R. H. 2007; 22 (3): 710-718
  • Thermomechanical properties of thin organosilicate glass films treated with ultraviolet-assisted cure ACTA MATERIALIA Iacopi, F., Beyer, G., Travaly, Y., Waldfried, C., Gage, D. M., Dauskardt, R. H., Houthoofd, K., Jacobs, P., Adriaensens, P., Schulze, K., Schulz, S. E., List, S., Carlotti, G. 2007; 55 (4): 1407-1414
  • Assessing the effect of die sealing in Cu/low-k structures 10th Annual International Interconnect Technology Conference (IITC) Kearney, A. V., Vairagar, A. V., Geisler, H., Zschech, E., Dauskardt, R. H. IEEE. 2007: 138–140
  • Time-Dependant Intercellular Delamination of Human Stratum Corneum Journal of Materials Science Wu, K., S., Li, J., Ananthapadmanabhan, K., P., Dauskardt, R., H. 2007; 42: 8986 – 8994
  • Diffusion of Aqueous Solutions into Hydrophobic Nanoporous Thin-Films Journal of Materials Research Guyer, E., P., Gantz, J., Dauskardt, R., H. 2007; 3 (22): 710-718
  • Adhesion between template materials and UV-cured nanoimprint resists J. Vac. Sci. Technol. B Houle, F., A., Guyer, E., P., Miller, D., C., Dauskardt, R., H. 2007; 4 (25): 1179
  • A Novel Bonding Technique Using Metal-Induced Crystallization of Amorphous Silicon Mater. Res. Soc. Symp. Proc. Ong, Markus, D., Dauskardt, Reinhold, H. 2007
  • Stress and Slurry Chemistry Effects on CMP Damage of Ultra-Low-k Dielectrics Kim, T., Zhong, Q., Peterson, M., Tam, H., Konno, T., Dauskardt, Reinhold, H. 2007
  • Effect of Silane Functional Group on Adhesion of Selected Epoxies for Microelectronic Packaging Journal of Microelectronics and Electronic Packaging Borrego, M., Jenkins, Dauskardt, R., H., Bravman, J., C. 2007; 1 (4): 8-15
  • Anomalous Debonding Behavior of a Polymer/Inorganic Interface Acta Materialia Sharratt, B., M., Wang, L., C., Dauskardt, R., H. 2007; 55: 3601–3609
  • Response to Comments on The Fatigue Endurance Limit of a Zr-Based Bulk Metallic Glass Scripta Materialia Menzel, B., Dauskardt, R., H. 2007; 57: 69–71
  • Molecular Network Reinforcement of sol-gel glasses Advanced Materials Dubois, G., Volksen, W., Magbitang, T., Miller, R., D., Gage, D., M., Dauskardt, R., H. 2007; 19: 3989–3994
  • Assessing the Effect of Die Sealing in Cu/Low-k Structures Kearney, Andrew, V., Vairagar, Anand, V., Geisler, H., Zschech, E., Dauskardt, Reinhold, H. 2007
  • Thermo-mechanical properties of thin organosilicate glass films treated with Ultra-Violet –assisted cure Acta Materialia Iacopia, F., Beyer, G., Travaly, Y., Waldfried, C., Gage, D., M., Dauskardt, R., H. 2007; 4 (55): 407-1414
  • Stress and slurry chemistry effects on CMP damage of ultra-low-k dielectrics 10th Annual International Interconnect Technology Conference (IITC) Kim, T., Zhong, Q., Peterson, M., Tam, H., Konno, T., Dauskardt, R. H. IEEE. 2007: 129–131
  • A novel bonding technique using metal-induced crystallization of amorphous silicon Symposium on Amorphous and Polycrystalline Thin-Film Silicon Science and Technology held at the 2007 MRS Spring Meeting Ong, M. D., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2007: 109–114
  • Influence of porosity and film thickness on adhesion of nanoporous organic dielectrics Advanced Metallization Conference 2006 Kearney, A. V., Chang, H., Mills, M. E., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2007: 517–520
  • Effect of UV cure on adhesive and cohesive failure of low-k films: Implications for integration Advanced Metallization Conference 2006 Gage, D. M., Stebbins, J. F., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2007: 327–330
  • Non-uniform UV curing effects on mechanical and fracture properties of organosilicate low-k thin films Advanced Metallization Conference 2006 Kim, T., Tsuji, N., Kemeling, N., Matsushita, K., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2007: 389–394
  • Graded delamination behavior of human stratum corneum BIOMATERIALS Wu, K. S., Stefik, M. M., Ananthapadmanabhan, K. P., Dauskardt, R. H. 2006; 27 (34): 5861-5870

    Abstract

    An in vitro adhesion test method has been adapted to quantify the through-thickness intercellular delamination energy of isolated human stratum corneum (SC). Both untreated and delipidized tissues were tested. Measured delamination energies were found to increase from approximately 3 J/m(2) near the surface to approximately 15 J/m(2) for the inner layers of the tissue. For delipidized SC, the location of the initial debond was located closer to the center of the tissue. Delamination energy values were elevated compared to untreated specimens, increasing from approximately 7 J/m(2) near the surface to approximately 18 J/m(2) for the inner layers of the SC. Further tests were run to measure delamination energies of SC as a function of hydration (15-100% relative humidity (RH)) at approximately 25 degrees C and as a function of temperature (10-90 degrees C) at several hydrations (15, 45, 100% RH). Delamination energies were observed to decrease with increasing hydration and increasing temperature with the most significant changes occurring for 100% RH conditioned SC. Additional SC was treated with pH-buffered solutions (pH 4.2, 6.7, 9.9) and selected surfactant solutions (1%, 10% wt/wt sodium dodecyl sulfate (SDS)) for comparison to untreated controls. While statistically significant differences were observed, the SC was found to be resistant to large changes in delamination energy with pH and 1% wt/wt SDS treatments with values in the range 4.2-5.1J/m(2) compared to control values of 4.4 J/m(2). More substantially elevated values were observed for SC treated with a 10%wt/wt SDS solution (6.6J/m(2)) and a chloroform-methanol extraction (11.2J/m(2)).

    View details for DOI 10.1016/j.biomaterials.2006.08.008

    View details for Web of Science ID 000241272300013

    View details for PubMedID 16934326

  • Mode II fracture behavior of a Zr-based bulk metallic glass JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS Flores, K. M., Dauskardt, R. H. 2006; 54 (11): 2418-2435
  • The fatigue endurance limit of a Zr-based bulk metallic glass SCRIPTA MATERIALIA Menzel, B. C., Dauskardt, R. H. 2006; 55 (7): 601-604
  • Fracture of nanoporous methyl silsesquioxane thin-film glasses JOURNAL OF MATERIALS RESEARCH Guyer, E. P., Patz, M., Dauskardt, R. H. 2006; 21 (4): 882-894
  • Short-ranged structural rearrangement and enhancement of mechanical properties of organosilicate glasses induced by ultraviolet radiation JOURNAL OF APPLIED PHYSICS Iacopi, F., Travaly, Y., Eyckens, B., Waldfried, C., Abell, T., Guyer, E. P., Gage, D. M., Dauskardt, R. H., Sajavaara, T., Houthoofd, K., Grobet, P., Jacobs, P., Maex, K. 2006; 99 (5)

    View details for DOI 10.1063/1.2178393

    View details for Web of Science ID 000236002900019

  • Stress-life fatigue behavior of a Zr-based bulk metallic glass ACTA MATERIALIA Menzel, B. C., Dauskardt, R. H. 2006; 54 (4): 935-943
  • Fatigue damage in bulk metallic glass I: Simulation SCRIPTA MATERIALIA Cameron, K. K., Dauskardt, R. H. 2006; 54 (3): 349-353
  • Fatigue damage in bulk metallic glass II: Experiments SCRIPTA MATERIALIA Hess, P. A., Menzel, B. C., Dauskardt, R. H. 2006; 54 (3): 355-361
  • Mechanical properties of human stratum corneum: Effects of temperature, hydration, and chemical treatment BIOMATERIALS Wu, K. S., van Osdol, W. W., Dauskardt, R. H. 2006; 27 (5): 785-795

    Abstract

    An in vitro mechanics approach to quantify the intercellular delamination energy and mechanical behavior of isolated human stratum corneum (SC) in a direction perpendicular to the skin surface is presented. The effects of temperature, hydration, and a chloroform-methanol treatment to remove intercellular lipids were explored. The delamination energy for debonding of cells within the SC layer was found to be sensitive to the moisture content of the tissue and to the test temperature. Delamination energies for untreated stratum corneum were measured in the range of 1-8J/m(2) depending on test temperature. Fully hydrated specimen energies decreased with increasing temperature, while room-humidity-hydrated specimens exhibited more constant values of 2-4J/m(2). Lipid-extracted specimens exhibited higher delamination energies of approximately 12J/m(2), with values decreasing to approximately 4J/m(2) with increasing test temperature. The peak separation stress decreased with increasing temperature and hydration, but lipid-extracted specimens exhibited higher peak stresses than untreated controls. The delaminated surfaces revealed an intercellular failure path with no evidence of tearing or fracture of cells. The highly anisotropic mechanical behavior of the SC is discussed in relation to the underlying SC structure.

    View details for DOI 10.1016/j.biomaterials.2005.06.019

    View details for Web of Science ID 000233858000012

    View details for PubMedID 16095683

  • UV curing effects on glass structure and mechanical properties of organosilicate low-k thin films 9th International Interconnect Technology Conference (IITC) Gage, D. M., Guyer, E. P., Stebbins, J. F., Cui, Z., Al-Bayati, A., Demos, A., MacWilliams, K. P., Dauskardt, R. H. IEEE, ELECTRON DEVICES SOC & RELIABILITY GROUP. 2006: 149–151
  • Adhesion between template materials and UV-cured nanoimprint resists Conference on Advances in Resist Technology and Processing XXIII Houle, F. A., Guyer, E., Miller, D. C., Dauskardt, R., Rice, E., Hamilton, J. SPIE-INT SOC OPTICAL ENGINEERING. 2006: U548–U555

    View details for DOI 10.1117/12.655698

    View details for Web of Science ID 000238175500047

  • Short-ranged structural rearrangement and enhancement of mechanical properties of organosilicate glasses induced by UltraViolet radiation Journal of Applied Physics Dauskardt, R., H., Iacopi, F., Travaly, Y., Eyckens, B., Waldfried, C., Guyer, T. 2006; 99: 053511-1 - 053511-7
  • Adhesion between template materials and UV-cured nanoimprint resists Houle, F., A., Guyerb, E., Millera, D., C., Dauskardt, R., H., Rice, E., Hamilton, J. 2006
  • Stress and Slurry Chemistry Effects on Cracking and Damage Evolution during CMP: Implications for Next Technology Nodes Twelfth International Conference on Chemical-Mechanical Polish (CMP) Planarization for ULSI Multilevel Interconnection (CMP-MIC) Dauskardt, Reinhold, H., Kim, T., Zhong, Q., Peterson, M., Tam, H., Konno, T. 2006
  • Non-Uniform UV Curing Effects on Mechanical and Fracture Properties of Organosilicate Low-k Thin Films Kim, T., Tsuji, N., Kemeling, N., Matsushita, K., Dauskardt, R., H. 2006
  • Effect of UV Cure on Adhesive and Cohesive Failure of Low-k Films: Implications for Integration Gage, D., M., Stebbins, J., F., Dauskardt, R., H. 2006
  • Fracture of Nanoporous Methyl Silsesquioxane Thin-Film Glasses Journal of Materials Research Guyer, E., P., Patz, M., Dauskardt, R., H. 2006; 4 (21)
  • The Role of Nanoscale Confinement of Adhesion Promoting Molecules on the Adhesion and Resistance to Moisture Attack at the Polymer/Silicon Nitride Interface Sharratt, B., M., Dauskardt, R., H. 2006
  • Influence of Porosity and Film Thickness on Adhesion of Nanoporous Organic Dielectrics Kearney, Andrew, V., Chang, H., Mills, Michael, E., Dauskardt, Reinhold, H. 2006
  • Stress-Life Fatigue Behavior of a Zr-Based Bulk Metallic Glass Acta Materialia Menzel, B., Dauskardt, R., H. 2006; 4 (54): 935 - 943
  • Mode II Fracture Behavior of a Zr-Based Bulk Metallic Glass Journal of the Mechanics and Physics of Solids Flores, K., M., Dauskardt, R., H. 2006; 11 (54): 2418 – 2435
  • Effects of Nonionic Surfactants on the Fracture of Nanoporous Methylsilsesquioxane Thin-Film Glasses International Conference of Planarization/CMP Technology Kim, T., Zhong, Q., Peterson, M., Tam, H., Konno, T., Dauskardt, Reinhold, H. 2006
  • The Fatigue Endurance Limit of a Zr-Based Bulk Metallic Glass Scripta Materialia Menzel, B., Dauskardt, R., H. 2006; 55: 601 - 604
  • UV-assisted curing: an effective technique for toughening low-k organosilicate films 22nd Annual Advanced Metallization Conference (AMC) Iacopi, F., Waldfried, C., Houthoofd, K., Guyer, E. P., Gage, D. M., Carlotti, G., Travaly, Y., Abell, T., Escorcia, O., Beyer, G., Berry, I., Dauskardt, R. H., Maex, K. MATERIALS RESEARCH SOCIETY. 2006: 247–254
  • Fracture properties of porous MSSQ films: Impact of porogen loading and burnout Symposium on Materials, Technology and Reliability of Low-k Dielectrics and Copper Interconnects held at the 2006 MRS Spring Meeting Ong, M. D., Jousseaume, V., Maitrejean, S., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2006: 15–20
  • Residual stress effects on plastic deformation and interfacial fracture in thin-film structures ACTA MATERIALIA Litteken, C. S., Strohband, S., Dauskardt, R. H. 2005; 53 (7): 1955-1961
  • Indentation fracture toughness of amorphous steel JOURNAL OF MATERIALS RESEARCH Hess, P. A., Poon, S. J., Shiflet, G. J., Dauskardt, R. H. 2005; 20 (4): 783-786
  • Effect of solution pH on the accelerated cracking of nanoporous thin-film glasses JOURNAL OF MATERIALS RESEARCH Guyer, E. P., Dauskardt, R. H. 2005; 20 (3): 680-687
  • Comparison of the telephone cord delamination method for measuring interfacial adhesion with the four-point bending method ACTA MATERIALIA Lee, A., Litteken, C. S., Dauskardt, R. H., Nix, W. D. 2005; 53 (3): 609-616
  • Effect of porosity on reducing cohesive strength and accelerating crack growth in ultra low-k thin-films IEEE International InterconnectTechnology Conference 2005 Guyer, E. P., Dauskardt, R. H. IEEE. 2005: 223–225
  • Benchmarking four point bend adhesion testing: The effect of test parameters on adhesion energy 5th Conference on Characterization and Metrology for ULSI Technology Cui, Z. J., Dixit, G., Xia, L. Q., Demos, A., Kim, B. H., Witty, D., M'Saad, H., Dauskardt, R. H. AMER INST PHYSICS. 2005: 507–511
  • Accelerated Debonding and Cracking in Thin-Film Structures: Chemical Reaction Rate and Loading Effects Guyer, E., P., Dauskardt, R., H. 2005
  • Effect of Solution pH on the Accelerated Cracking of Nanoporous Thin-Films Glasses Journal of Materials Research Guyer, E., P., Dauskardt, R., H. 2005; 3 (20): 680 – 687
  • Mechanisms of Fatigue Damage Formation and Evolution in Zr-Based Bulk Metallic Glass Hess, P., A., Menzel, B., Dauskardt, R., H. 2005
  • Fracture in Thin-Film Structures for Device Technologies: New Material and Length Scale Challenges Litteken, C., Dauskardt, R., H. 2005
  • Effect of interface chemistry and thermomechanical loading on debonding of polymer/silicon interfaces: Implications for device reliability. Sharratt, B., M., Wang, L., C., Dauskardt, R., H. 2005
  • Effects of Friction and Loading Parameters on Four-Point Bend Adhesion Measurements of Low-k Thin Film Interconnect Structures Gage, D., M., Kim, K., Litteken, C., S., Dauskardt, R., H. 2005
  • Indentation Fracture Toughness of Amorphous Steel Journal of Materials Research Hess, P., A., Poon, S., J., Shiflet, G., J., Dauskardt, R., H. 2005; 4 (20): 783 – 786
  • Benchmarking Four Point Bend Adhesion Testing: The Effect of Test Parameters On Adhesion Energy 2005 International Conference on Characterization and Metrology for ULSI Technology Dauskardt, R., H., Cui, Z., Dixit, G., Xia, L., Demos, A., Witty, B., H. 2005
  • Mechanical Properties of Human Stratum Corneum: Effects of Temperature, Hydration, and Chemical Treatment Biomaterials Wu, K., S., Osdol, W., W. van, Dauskardt, R., H. 2005; 5 (27): 785-795
  • Effects of friction and loading parameters on four-point bend adhesion measurements of low-k thin film interconnect structures IEEE International InterconnectTechnology Conference 2005 Gage, D. M., Kim, K., Litteken, C. S., Dauskardt, R. H. IEEE. 2005: 42–44
  • Electrical technique for monitoring crack growth in thin-film fracture mechanics specimens JOURNAL OF MATERIALS RESEARCH Guyer, E. P., Dauskardt, R. H. 2004; 19 (11): 3139-3144
  • Failure of medullary tubes - A materials analysis INJURY-INTERNATIONAL JOURNAL OF THE CARE OF THE INJURED Taub, M., Wera, G., Dauskardt, R. H., Mohler, D. G. 2004; 35 (9): 878-882

    Abstract

    The objective of this study is to determine the effects of autoclaving on the stress, strain, ultimate tensile strength (UTS), fracture strain, modulus, and yield stress of nylon medullary tubes. There are three reports describing nylon medullary tube failure in the literature. All cases involved the use of nylon medullary tubes during open reduction internal fixation of fractured long bones. We demonstrated increased brittleness and decreased strength with increased exposure of medullary tubes to autoclaving, most dramatically after 100 autoclave cycles. Visual inspection of tubes is a clear indication of material degradation after repeated autoclaving. Furthermore, there is a significant difference in ultimate tensile strength (P < 0.0001) between tubes exposed to less than 100 sterilization cycles compared to tubes exposed to greater than 100 cycles. Likewise, there is a significant decrease in yield stress (P < 0.0004) between the same groups. We recommend disposal and replacement of nylon medullary tubes before they are exposed to 100 autoclaving cycles in order to avoid failure of the device.

    View details for DOI 10.1016/S0020-1383(03)00307-3

    View details for PubMedID 15302240

  • Fatigue crack growth in micro-machined single-crystal silicon JOURNAL OF MATERIALS RESEARCH Renuart, E. D., Fitzgerald, A. M., Kenny, T. W., Dauskardt, R. H. 2004; 19 (9): 2635-2640
  • Mechanisms of elevated temperature fatigue crack growth in Zr-Ti-Cu-Ni-Be bulk metallic glass ACTA MATERIALIA Hess, P. A., Dauskardt, R. H. 2004; 52 (12): 3525-3533
  • Toughening of nanoporous glasses using porogen residuals NATURE MATERIALS Maidenberg, D. A., Volksen, W., Miller, R. D., Dauskardt, R. H. 2004; 3 (7): 464-469

    Abstract

    Nanoporous glasses are inherently brittle materials that become increasingly fragile with increasing porosity. We show that remarkable increases in fracture energy can be obtained from remnants of the porogen molecules used to create the nanoscale pores. The interfacial fracture energy of approximately 2.6 J m(-2) for dense methylsilsesquioxane glass films is shown to increase by over one order of magnitude to >30 J m(-2) for glasses containing 50 vol.% porosity. The increased fracture resistance is related to a powerful molecular-bridging mechanism that was modelled using bridging mechanics. The study demonstrates that significant increases in interfacial fracture energy may be obtained using strategies involving controlled decomposition of the porogen molecule during processing of nanoporous glasses. The implications are important for a range of emerging optical, electronic and biological technologies that use nanoporous thin films, but are limited by the degradation of mechanical properties with increasing porosity.

    View details for DOI 10.1038/nmat1153

    View details for Web of Science ID 000222389100015

    View details for PubMedID 15220912

  • Fracture and deformation of bulk metallic glasses and their composites International Symposium on Intermetallic and Advanced Materials Flores, K. M., Dauskardt, R. H. ELSEVIER SCI LTD. 2004: 1025–29
  • Accelerated crack growth of nanoporous low-k glasses in CMP slurry enviromments 7th Annual International Interconnect Technology Conference Guyer, E. P., Dauskardt, R. H. IEEE. 2004: 236–238
  • The prospects for mechanical ratcheting of bulk metallic glasses Symposium on Amorphous and Nanocrystalline Metals held at the 2003 MRS Fall Meeting Wright, W. J., Dauskardt, R. H., Nix, W. D. MATERIALS RESEARCH SOCIETY. 2004: 319–324
  • Accelerated Crack Growth of Nanoporous Low-k Glasses in CMP Slurry Environment Guyer, E., P., Dauskardt, R., H. 2004
  • Reliability of Thin-Film Structures for Device Technologies: Adhesion, New Materials and Length Scale Challenges Interfaces In Electronic Materials, Electrochemical Society Guyer, E., P., Litteken, C., Maidenberg, D., Dauskardt, R., H. 2004
  • Effect of Aqueous Solution Chemistry on the Accelerated Cracking of Lithographically Patterned Arrays of Copper and Nanoporous Thin-Films MRS Symposium ProceedingsMaterials Research Society Guyer, E., P., Dauskardt, R., H. 2004
  • Electrical Resistance Technique to Measure Crack Length in Fracture Mechanics Specimens Containing Thin-Film Structures Journal of Materials Research Guyer, E., P., Dauskardt, R., H. 2004; 11 (19): 3139-3144
  • Fatigue Loading Effects on Underfull/Passivation Interface Reliability for High Density Packaging Sharratt, B., Dauskardt, R., H. 2004
  • Debonding under fatigue loading at polymer/inorganic interfaces. Sharratt, B., M., Dauskardt, R., H. 2004
  • Accelerated Crack Growth of Nanoporous Low-k Glasses in Aqueous Solutions Guyer, E., P., Dauskardt, R., H. 2004
  • Fracture and Deformation of Metallic Glasses and their Composites Intermetallics Flores, K., M., Dauskardt, R., H. 2004; 7-9 (12): 1025-1029
  • Failure of Medullary Tubes: A Materials Analysis Injury, International Journal of the Care of the Injured Taub, M., B., Wera, G., Dauskardt, R., H., Mohler, D., G. 2004; 35: 878 – 882
  • Fatigue Crack Growth in Micro-Machined Single Crystal Silicon Specimens Journal of Materials Research Renuart, E., Fitzgerald, A., M., Kenny, T., W., Dauskardt, R., H. 2004; 9 (19): 2635-2640
  • Toughening of Nanoporous Glasses Using Porogen Residuals Nature Materials Maidenberg, D., A., Volksen, W., Miller, R., D., Dauskardt, R., H. published online. 2004: 464–469
  • Important Factors for Silane Adhesion: Surface Coverage, Functionality, and Chain Length Journal of Adhesion Science and Technology Jenkins, M., L., Dauskardt, R., H., Bravman, J., C. 2004; 13 (18): 1483 -1588
  • Fracture of Nanoporous Thin-Film Glasses Nature Materials Guyer, E., P., Dauskardt, R., H. 2004; 3: 53–57
  • Elevated Temperature Fatigue Crack Propagation of a Zr-Based Bulk Metallic Glass Acta Materialia Hess, P., A., Dauskardt, R., H. 2004; 12 (52): 3525-3533
  • Effect of aqueous solution chemistry on the accelerated cracking of lithographically patterned arrays of copper and nanoporous thin-films Synposium on Materials, Technology and Reliability for Advanced Interconnects and Low-k Dielectrics held at the 2004 MRS Spring Meeting Guyer, E. P., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2004: 303–308
  • Transient fatigue crack-growth behavior and damage zones in Zr-based bulk metallic glass Symposium on Amorphous and Nanocrystalline Metals held at the 2003 MRS Fall Meeting Hess, P. A., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2004: 325–330
  • Debonding under fatigue loading at polymer/inorganic interfaces Symposium on Nanoscale Materials and Modeling held at the 2004 MRS Spring Meeting Sharratt, B. M., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2004: 363–368
  • Special issue on fatigue of advanced materials - Preface MECHANICS OF MATERIALS Soboyejo, W. O., Dauskardt, R., Ritchie, R. O. 2004; 36 (1-2): 1-1
  • Important factors for silane adhesion promoter efficacy: surface coverage, functionality and chain length JOURNAL OF ADHESION SCIENCE AND TECHNOLOGY JENKINS, M. L., Dauskardt, R. H., Bravman, J. C. 2004; 18 (13): 1497-1516
  • Fracture of nanoporous thin-film glasses NATURE MATERIALS Guyer, E. P., Dauskardt, R. H. 2004; 3 (1): 53-57

    Abstract

    Fracture of nanoporous thin-film glasses is a significant challenge for the integration of these mechanically fragile materials in emerging microelectronic and biological technologies. In particular, the integration of these materials has been limited by accelerated cracking rates in moist environments leading to premature failure. Here, we demonstrate how cracking is affected by aqueous solution chemistry, and reveal anomalously high crack-growth rates in hydrogen peroxide solutions frequently encountered during device processing or when in use. Kinetic mechanisms involving the transport and steric hindrance of reactive hydrogen peroxide molecules at the crack tip are proposed. Thin-film design strategies that involve energy dissipation by local plasticity in thin ductile layers on increasing the resistance to cracking of nanoporous glass layers is demonstrated. Understanding how aqueous solutions influence cracking and associated device reliability is a fundamental challenge for these promising materials to be viable candidates for new technologies.

    View details for DOI 10.1038/nmat1037

    View details for Web of Science ID 000187746000016

    View details for PubMedID 14661017

  • Fracture and fatigue behavior of a Zr-Ti-Nb ductile phase reinforced bulk metallic glass matrix composite SCRIPTA MATERIALIA Flores, K. M., Johnson, W. L., Dauskardt, R. H. 2003; 49 (12): 1181-1187
  • Stress wave interference effects during fracture of silicon micromachined specimens EXPERIMENTAL MECHANICS Fitzgerald, A. M., Kenny, T. W., Dauskardt, R. H. 2003; 43 (3): 317-322
  • Temperature dependence of positron annihilation in a Zr-Ti-Ni-Cu-Be bulk metallic glass JOURNAL OF MATERIALS RESEARCH Suh, D., Dauskardt, R. H., Asoka-Kumar, P., Sterne, P. A., Howell, R. H. 2003; 18 (9): 2021-2024
  • Comments on "Mechanical relaxation time scales in a Zr-Ti-Ni-Cu-Be bulk metallic glass" by Daewoong Suh and Reinhold H. Dauskardt [J. Mater. Res. 17, 1254 (2002)] - Reply to the comments of K. Schroter JOURNAL OF MATERIALS RESEARCH Suh, D., Dauskardt, R. H. 2003; 18 (8): 2000-2001
  • Notch strength insensitivity of self-setting hydroxyapatite bone cements JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE Morgan, J. P., Dauskardt, R. H. 2003; 14 (7): 647-653

    Abstract

    The effect of notches on the strength properties of self-setting hydroxyapatite (HA) cements is examined. Such stress concentrators may be present at orthopedic repair sites employing cements and significantly affect their mechanical reliability. Notched tensile specimens were prepared from two cement compositions that resulted in HA and carbonated apatite. The notch radii was varied from 0.15 to 6 mm with a fixed length of 6 mm. The strength of the cements was found to be surprisingly insensitive to the presence of the notches over the range of notch radii examined. A fracture statistics model incorporating a Weibull statistical approach was employed to rationalize the observed notch insensitivity.

    View details for Web of Science ID 000183329700013

    View details for PubMedID 15348429

  • Interface separation in residually-stressed thin-film structures INTERFACE SCIENCE Strohband, S., Dauskardt, R. H. 2003; 11 (3): 309-317
  • Effects of open-volume regions on relaxation time-scales and fracture behavior of a Zr-Ti-Ni-Cu-Be bulk metallic glass Annual Meeting of the Minerals-Metals-and-Materials-Society Suh, D., Dauskardt, R. H. ELSEVIER SCIENCE BV. 2003: 181–86
  • Fracture nanomechanics - Preface INTERNATIONAL JOURNAL OF FRACTURE Gerberich, W. W., Dauskardt, R. H. 2003; 119 (4-2): VII-VII
  • Effects of Open-Volume Regions on Internal Times Scales and Fracture Behavior of a Zr-Ti-Ni-Cu-Be Bulk Metallic Glass Journal of Non-Crystalline Solids Suh, D., Dauskardt, R., H. 2003; 1-2 (317): 181 – 186
  • Authors’ Reply to the Comment on "Mechanical Relaxation Time Scales in a Zr-Ti-Ni-Cu-Be Bulk Metallic Glass" Journal of Materials Research Suh, D., Dauskardt, R., H. 2003; 8 (18): 2000 – 2001
  • Interfacial Adhesion of Thin-Film Patterned Interconnect Structures Litteken, C., Dauskardt, R., Scherban, T., Xu, G., Leu, J., Gracias, D. 2003
  • Interface Separation in Residually Stressed Thin-Film Structures Interface Science special issue on “Mechanics of Interfaces” Stroband, S., Dauskardt, R., H. 2003; 3 (11): 309-317
  • Fracture Nanomechanics International Journal of Fracture Gerberich, W., W., Dauskardt, R., H. Kluwer Academic Press, Dordrecht, Netherlands. 2003
  • Multi-Scale Simulations Of Interfacial Fracture Of Nanoscale Thin-Film Structures: Effect Of Length Scales and Residual Stresses Stroband, S., Dauskardt, R., H. 2003
  • Effect of CMP Slurry Environments on Subcritical Crack Growth in Ultra Low-k Dielectric Materials Guyer, E., P., Dauskardt, R., H. 2003
  • Effects of Templating Byproducts on Adhesion of Nanoporous Dielectric Films Maidenberg, D., A., Volksen, W., Miller, R., D., Dauskardt, R., H. 2003
  • Stress Wave Interference Effects during Fracture of Silicon Micromachined Specimens Journal of Experimental Mechanics Fitzgerald, A., M., Dauskardt, R., H., Kenny, T., W. 2003; 3 (43): 317 – 322
  • Notch Strength Insensitivity of Self-Setting Hydroxyapatite Bone Cements Journal of Materials Science: Materials in Medicine Morgan, J., P., Dauskardt, R., H. 2003; 14: 647 – 653
  • Temperature Dependence of Positron Annihilation in a Zr-Ti-Ni-Cu-Be Bulk Metallic Glass: Shallow versus Deep Traps Journal of Materials Research Suh, D., Asoka-Kumar, P., Sterne, P., A., Howell, R., H., Dauskardt, R., H. 2003; 9 (18): 2021-2024
  • Interfacial adhesion of thin-film patterned interconnect structures 6th Annual International Interconnect Technology Conference Litteken, C., Dauskardt, R., Scherban, T., Xu, G., Leu, J., GRACIAS, D., Sun, B. IEEE. 2003: 168–170
  • Effects of templating byproducts on adhesion of nanoporous dielectric films 6th Annual International Interconnect Technology Conference Maidenberg, D., Volksen, W., Miller, R., Dauskardt, R. IEEE. 2003: 48–50
  • Interactions of hydrogen with amorphous nano-structure and their effects on relaxation behavior of Zr-Ti-Ni-Cu-Be bulk metallic glass alloys International Conference on Hydrogen Effects on Material Behavior and Corrosion Deformation Interactions Suh, D., Dauskardt, R. H. MINERALS, METALS & MATERIALS SOC. 2003: 183–190
  • Effect of CMP slurry environments on subcritical crack growth in ultra low-k dielectric materials 6th Annual International Interconnect Technology Conference Guyer, E. P., Dauskardt, R. H. IEEE. 2003: 89–91
  • The effect of atomic-scale open-volume on flow and fracture processes in a Zr-Ti-Ni-Cu-Be bulk metallic glass Symposium on Supercooled Liquids, Glass Transition and Bulk Metallic Glasses Suh, D., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2003: 249–255
  • Multi-scale simulations of interfacial fracture of nanoscale thin-film structures: Effect of length scales and residual stresses Symposium on Mechanical Properties Derived from Nanostructuring Materials held at the 2003 MRS Spring Meeting Strohband, S., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2003: 303–308
  • Elevated temperature fatigue crack propagation of a Zr-Ti-Cu-Ni-Be bulk metallic glass Symposium on Supercooled Liquids, Glass Transition and Bulk Metallic Glasses Hess, P. A., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2003: 237–242
  • Effect of moisture and graded-layer mechanical properties on deformation and interfacial adhesion Symposium on Mechanical Properties Derived from Nanostructuring Materials held at the 2003 MRS Spring Meeting Wang, L. C., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2003: 227–232
  • Adhesion of polymer thin-films and patterned lines INTERNATIONAL JOURNAL OF FRACTURE Litteken, C. S., Dauskardt, R. H. 2003; 119 (4-2): 475-485
  • Flow and fracture in Zr-based bulk metallic glasses ANNALES DE CHIMIE-SCIENCE DES MATERIAUX Suh, D., Dauskardt, R. H. 2002; 27 (5): 25-40
  • Opportunities for materials characterization using high-energy positron beams APPLIED SURFACE SCIENCE Asoka-Kumar, P., Howell, R., Nieh, T. G., Sterne, P. A., Wirth, B. D., Dauskardt, R. H., Flores, K. M., Suh, D., ODETTE, G. R. 2002; 194 (1-4): 160-167
  • Mechanical relaxation time scales in a Zr-Ti-Ni-Cu-Be bulk metallic glass JOURNAL OF MATERIALS RESEARCH Suh, D. W., Dauskardt, R. H. 2002; 17 (6): 1254-1257
  • Subcritical debonding of polymer/silica interfaces under monotonic and cyclic loading Symposium on Computational Thermodynamics and Materials Design Snodgrass, J. M., Pantelidis, D., JENKINS, M. L., Bravman, J. C., Dauskardt, R. H. PERGAMON-ELSEVIER SCIENCE LTD. 2002: 2395–2411
  • Characterization of free volume in a bulk metallic glass using positron annihilation spectroscopy JOURNAL OF MATERIALS RESEARCH Flores, K. M., Suh, D., Dauskardt, R. H., Asoka-Kumar, P., Sterne, P. A., Howell, R. H. 2002; 17 (5): 1153-1161
  • Subcritical crack growth in single-crystal silicon using micromachined specimens JOURNAL OF MATERIALS RESEARCH Fitzgerald, A. M., Iyer, R. S., Dauskardt, R. H., Kenny, T. W. 2002; 17 (3): 683-692
  • The effects of hydrogen on viscoelastic relaxation in Zr-Ti-Ni-Cu-Be bulk metallic glasses: implications for hydrogen embrittlement ACTA MATERIALIA Daewoong, S., Asoka-Kumar, P., Dauskardt, R. H. 2002; 50 (3): 537-551
  • Moisture-assisted subcritical debonding of a polymer/metal interface JOURNAL OF APPLIED PHYSICS Kook, S. Y., Dauskardt, R. H. 2002; 91 (3): 1293-1303
  • Adhesion and reliability of underfill/subtrate interfaces in flip chip BGA packages: Metrology and characterization 27th Annual International Electronics Manufacturing Technology Symposium (IEMT) Nagarajan, K., Dauskardt, R. H. IEEE. 2002: 206–214
  • Effect of Composition and Bead Settling on Debonding of Underfill Layers Wang, L., Dauskardt, R., H. 2002
  • Interactions of Hydrogen with Amorphous Nano-Structure and Their Effects on Relaxation Behavior of Zr-Ti-Ni-Cu-Be Bulk Metallic Glass International Conference On Hydrogen Effects on Material Behavior and Corrosion Deformation Interactions, Jackson Lake Lodge Moran Suh, D., Dauskardt, R., H. 2002
  • The Effects of Hydrogen on Viscoelastic Relaxation in Zr-Ti-Ni-Cu-Be Bulk Metallic Glasses: Implications for Hydrogen Enbrittlement Acta Materialia Suh, D., Asoka-Kumar, P., Dauskardt, R., H. 2002; 3 (50): 537-551
  • Characterization of Free Volume in Bulk Metallic Glass Using Positron Annihilation Spectroscopy Journal of Materials Research Flores, K., M., Suh, D., Asoka-Kumar, P., Sterne, P., A., Howell, R., Dauskardt, R., H. 2002; 5 (17): 1153-1161
  • The Effect of Atomic-Scale Open-Volume on Flow and Fracture Processes in a Zr-Ti-Ni-Cu-Be Bulk Metallic Glass Suh, D., Dauskardt, R., H. 2002
  • Mechanical Relaxation Times Scales in a Zr-Ti-Ni-Cu-Be Bulk Metallic Glass Journal of Materials Research Suh, D., Dauskardt, R., H. 2002; 6 (17): 1254-1257
  • Subcritical Crack Growth in Single Crystal Silicon using Micro-Machined Specimens Journal of Materials Research Fitzgerald, A., M., Iyer, R., S., Dauskardt, R., H., Kenny, T., W. 2002; 3 (17): 683-692
  • Moisture-Assisted Debonding of a Polymer/Metal Interface Journal of Applied Physics Kook, S. -Y., Dauskardt, R., H. 2002; 3 (91): 1293-1303
  • Studies of silane adhesion promoters on silica filler particles for use in microelectronic packaging Symposium on Polymer Interfaces and Thin Films held at the 2001 MRS Fall Meeting Jenkins, M., DeVries, G., Dauskardt, R. H., Bravman, J. C. MATERIALS RESEARCH SOCIETY. 2002: 159–164
  • Mechanical and microstructural properties of stratum corneum Symposium on Biological and Biomimetic Materials - Properties to Function held at the 2002 MRS Spring Meeting Wu, K. S., Van Osd, W. W., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 2002: 27–33
  • Crack-tip plasticity in bulk metallic glasses 12th International Conference on the Strength of Materials (ICSMA 12) Flores, K. M., Dauskardt, R. H. ELSEVIER SCIENCE SA. 2001: 511–515
  • The effects of hydrogen on deformation and fracture of a Zr-Ti-Ni-Cu-Be bulk metallic glass 12th International Conference on the Strength of Materials (ICSMA 12) Suh, D., Dauskardt, R. H. ELSEVIER SCIENCE SA. 2001: 480–483
  • Environmental effects on interfacial adhesion 12th European Symposium on the Reliability of Electron Devices, Failure Physics and Analysis (ESREF 2001) Lane, M. W., Snodgrass, J. M., Dauskardt, R. H. PERGAMON-ELSEVIER SCIENCE LTD. 2001: 1615–24
  • Mean stress effects on flow localization and failure in a bulk metallic glass ACTA MATERIALIA Flores, K. M., Dauskardt, R. H. 2001; 49 (13): 2527-2537
  • Effects of pre-charged hydrogen on the mechanical and thermal behavior of Zr-Ti-Ni-Cu-Be bulk metallic glass alloys Bulk Metallic Glasses Conference Suh, D., Dauskardt, R. H. JAPAN INST METALS. 2001: 638–41
  • Flow and fracture of bulk metallic glass alloys and their composites Bulk Metallic Glasses Conference Flores, K. M., Suh, D., Howell, R., Asoka-Kumar, P., Sterne, P. A., Dauskardt, R. H. JAPAN INST METALS. 2001: 619–22
  • Effects of an adhesion promoter on the debond resistance of a metal-polymethylmethacrylate interface JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Ohashi, K. L., Yerby, S. A., Dauskardt, R. H. 2001; 54 (3): 419-427

    Abstract

    Debonding and premature failure of prostheticpolymethylmethacrylate interfaces have been shown to be exacerbated by exposure to physiological environment. In efforts to counteract these hydrolytic degradation effects, two clinically relevant Co-Cr-Mo surface morphologies were treated with an organosilane adhesion promoter (gamma-methacyloxypropyltrimethoxy) before interface bonding. Samples were quantitatively characterized in terms of the adhesion (fracture) and subcritical debond growth-rate (fatigue) behavior of the interface. The steady-state interface debond resistance, Gss (J/m2), was shown to increase with application of the silane pretreatment both in air (20 degrees C, 45% relative humidity) and simulated physiological environment (37 degrees C, Ringer's). Similarly, positive shifts in the subcritical debond threshold, deltaG(TH), values are observed for silane pretreated interfaces. A shift in the debond path from primarily adhesive failure in untreated surfaces to cohesive failure between the silane layer and bulk polymethylmethacrylate for silane treated surfaces was observed. Silane pretreatment of Co-Cr-Mo surfaces was shown to effectively limit the degree of the environmental degradation. General insights to the effects of surface roughness, chemical enhancement, and the environmental effects on the thermodynamics at the interface and resulting debond behavior are discussed.

    View details for Web of Science ID 000166128200016

    View details for PubMedID 11189050

  • Adhesion of benzocyclobutene-passivated silicon in epoxy layered structures JOURNAL OF MATERIALS RESEARCH Hohlfelder, R. J., Maidenberg, D. A., Dauskardt, R. H., Wei, Y. G., Hutchinson, J. W. 2001; 16 (1): 243-255
  • Studies of Silane Adhesion Promoters on Silica Filler Particles for use in Microelectronic Packaging Jenkins, M., DeVries, G., A., Dauskardt, R., H., Bravman, J., C. 2001
  • The Effects of Hydrogen on Deformation and Fracture of a Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Materials Science and Engineering Suh, D., Dauskardt, R., H. 2001: A319 – 321, 480 – 483
  • The Effects of Pre-Charged Hydrogen on the Mechanical and Thermal Behavior of Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Alloys Materials Transactions, JIM Suh, D., Dauskardt, R., H. 2001; 4 (42): 638-641
  • Adhesion and Debonding of Pressure Sensitive Adhesives Used in Transdermal Drug Delivery Systems Taub, M., Dauskardt, R., H. 2001
  • Adhesion Mechanisms of Silane Adhesion Promoters in Microelectronic Packaging Jenkins, M., Snodgrass, J., Chesterman, A., DeVries, G., Dauskardt, R., H., Bravman, J., C. 2001
  • Fatigue Processes in Single Crystal Silicon MEMS Devices Renuart, E., Fitzgerald, A., M., Kenny, T., W., Dauskardt, R., H. 2001
  • Crack Tip Plasticity in Bulk Metallic Glass Materials Science and Engineering Flores, K., M., Dauskardt, R., H. 2001: A319 - 321, 511 – 515
  • Plasticity contributions to interface adhesion in thin-film interconnect structures JOURNAL OF MATERIALS RESEARCH Lane, M., Dauskardt, R. H., Vainchtein, A., Gao, H. J. 2000; 15 (12): 2758-2769
  • Effects of fatigue loading and PMMA precoating on the adhesion and subcritical debonding of prosthetic-PMMA interfaces JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Ohashi, K. L., Dauskardt, R. H. 2000; 51 (2): 172-183

    Abstract

    Debonding of clinically relevant CoCrMo-polymethylmethacrylate (PMMA) interfaces is shown to occur subcritically under fatigue loading, implying that debonding may occur at loads much lower than those required for catastrophic failure. Interface fracture mechanics samples containing precoated and uncoated grit-blasted CoCrMo substrates and a PMMA layer were constructed and quantitatively evaluated in terms of their critical interface adhesion and subcritical debond behavior. The precoat surfaces had markedly enhanced adhesion and fatigue resistance in both air and simulated physiological environmental conditions compared to the uncoated samples. Constraint of the PMMA layer does not significantly affect the debond process for thickness between 2- and 5-mm. In addition, wear particles were collected and shown to be consistent with particle sizes reported in vivo and are on the scale of the metal surface roughness. Life prediction methods using the subcritical debond-growth data are discussed.

    View details for Web of Science ID 000087329300004

    View details for PubMedID 10825216

  • Fracture toughness and crack growth phenomena of plasma-etched single crystal silicon 10th International Conference on Solid-State Sensors and Actuators Fitzgerald, A. M., Dauskardt, R. H., Kenny, T. W. ELSEVIER SCIENCE SA. 2000: 194–99
  • Fracture and subcritical crack-growth behavior of Y-Si-Al-O-N glasses and Si3N4 ceramics JOURNAL OF THE AMERICAN CERAMIC SOCIETY BHATNAGAR, A., Hoffman, M. J., Dauskardt, R. H. 2000; 83 (3): 585-596
  • Hydrogen effects on the mechanical and fracture behavior of a Zr-Ti-Ni-Cu-Be bulk metallic glass SCRIPTA MATERIALIA Suh, D., Dauskardt, R. H. 2000; 42 (3): 233-240
  • Adhesion and reliability of copper interconnects with Ta and TaN barrier layers JOURNAL OF MATERIALS RESEARCH Lane, M., Dauskardt, R. H., Krishna, N., Hashim, I. 2000; 15 (1): 203-211
  • Flow and Fracture of Bulk Metallic Glass Alloys and Their Composites Flores, K., M., Suh, D., Howell, R., Asoka-Kumar, P., Sterne, P., A., Dauskardt, R., H. 2000
  • Adhesion of Benzocyclobutine-Passivated Silicon in Epoxy Layered Structures Journal of Materials Research Hohlfelder, R., J., Maidenberg, D., A., Dauskardt, R., H., Wei, Y., Hutchinson, J., W. 2000; 1 (16): 243-255
  • The effect of Fatigue on The Adhesion and Subcritical Debonding of Benzocyclobutene/Silicon Dioxide Interfaces Snodgrass, J., Dauskardt, R., H. 2000
  • Chemical and Structural Characterization of Silane Adhesion Promoting Films for Use in Microelectronic Packaging Jenkins, M., Snodgrass, J., Dauskardt, R., H., Bravman, J., C. 2000
  • Effects of an Adhesion Promoter on the Debond Resistance of a Metal-PMMA Interface Journal of Biomedical Materials Research Ohashi, K., L., Yerby, S., A., Dauskardt, R., H. 2000; 12: 419-427
  • Adhesion and Reliability of Underfill/Substrate interfaces in Microelectronic Packages: Metrology and Characterization SRC Consortium Meeting, Albany, New York Nagarajan, K., Dauskardt, R., H. 2000
  • Hydrogen Effects on the Mechanical and Fracture Behavior of a Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Scripta Materialia Suh, D., Dauskardt, R., H. 2000; 3 (42): 233-240
  • Fracture and Subcritical Crack-Growth Behavior of Y-Si-Al-O-N Glasses and Si3N4 Ceramics Journal of the American Ceramics Society Bhatnagar, A., Hoffmann, M., J., Dauskardt, R., H. 2000; 3 (83): 585-596
  • Atomic Force Microscopy Studies of Fracture Surfaces from Oxide/Polymer Interfaces Jenkins, M., Snodgrass, J., Chesterman, A., Dauskardt, R., H., Bravman, J., C. 2000
  • Adhesion of Pressure Sensitive Adhesives with Application in Transdermal Drug Delivery Taub, M., Dauskardt, R., H. 2000
  • Adhesion and Reliability of Methylsilsesquioxane Dielectric Materials Maidenberg, D., A., Volksen, W., Miller, R., D., Dauskardt, R., H. 2000
  • Short Range Chemical Ordering in Bulk Metallic Glasses Dauskardt, R., H., Sterne, P., A., Asoka-Kumar, P., Hartley, J., H., Howell, R., H., Nieh, T., G. 2000
  • Hydrogen Embrittlement in a Zr-Ti-Cu-Ni-Be Bulk Metallic Glass Suh, D., Dauskardt, R., H. 2000
  • Effects of Fatigue Loading and PMMA Precoating on the Adhesion and Subcritical Debonding of Prosthetic/PMMA Interfaces Journal of Biomedical Materials Research Ohashi, K., L., Dauskardt, R., H. 2000; 51: 172-183
  • Strength, Toughness and Fatigue of an Apatite Cement Jew, V., Morgan, J., P., Dauskardt, R., H. 2000
  • Fatigue and environmental effects on subcritical debonding of polymer interfaces SEM 9th International Congress on Experimental Mechanics Snodgrass, J. M., Dauskardt, R. H. SOC EXPERIMENTAL MECHANICS INC. 2000: 900–903
  • Study of crack propagation at an oxide/polymer interface under varying loading conditions Symposium V on Thin Films-Stresses and Mechanical Properties VIII held at the 1999 MRS Fall Meeting Pantelidis, D., Snodgrass, J., Dauskardt, R. H., Bravman, J. C. MATERIALS RESEARCH SOCIETY. 2000: 407–412
  • High-resolution measurement of crack growth in micro-machined single crystal silicon Symposium MM on Materials Science of Microelectromechanical Systems (MEMS) Devices II held at the 1999 MRS Fall Meeting Fitzgerald, A. M., Dauskardt, R. H., Kenny, T. W. MATERIALS RESEARCH SOCIETY. 2000: 43–48
  • Adhesion and mechanical reliability of microelectronic devices and their packages SEM 9th International Congress on Experimental Mechanics Dauskardt, R. H. SOC EXPERIMENTAL MECHANICS INC. 2000: 888–888
  • Enhanced toughness due to stable crack tip damage zones in bulk metallic glass SCRIPTA MATERIALIA Flores, K. M., Dauskardt, R. H. 1999; 41 (9): 937-943
  • Fatigue crack-growth behavior of materials in viscous fluid environments JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS Yi, K. S., Cox, B. N., Dauskardt, R. H. 1999; 47 (9): 1843-1871
  • Local heating associated with crack tip plasticity in Zr-Ti-Ni-Cu-Be bulk amorphous metals JOURNAL OF MATERIALS RESEARCH Flores, K. M., Dauskardt, R. H. 1999; 14 (3): 638-643
  • Subcritical debonding of multilayer interconnect structures: Temperature and humidity effects Materials Reliability in Microelectronics IX Symposium at the 1999 MRS Spring Meeting Lane, M., Dauskardt, R., Ma, Q., Fujimoto, H., Krishna, N. MATERIALS RESEARCH SOCIETY. 1999: 251–256
  • Subcritical Debonding of Multilayer Interconnect Structures: Temperature and Humidity Effects Lane, M., Dauskardt, R., H., Ma, Q., Fujimoto, H., Krishna, N. 1999
  • The Effect of Environment and Fatigue on the Adhesion and Subcritical Debonding of Dielectric Polymers Snodgrass, J., M., Pantelidis, D., Bravman, J., C., Dauskardt, R., H. 1999
  • Environmental and Stress State Effects on Fracture and Fatigue Crack-Growth in Zr-Ti-Ni-Cu-Be Bulk Amorphous Metals Flores, K., M., Suh, D., Dauskardt, R., H. edited by Inoue, A., Johnson, W., Liu, C., T. 1999
  • Study of Crack Propagation at an Oxide/Polymer Interface under Varying Loading Conditions Pantelidis, D., Snodgrass, J., Dauskardt, R., H., Bravman, J., C. 1999
  • Fracture Toughness of Plasma-Etched Single Crystal Silicon and Implications for MEMS Design in Symposium on Microelectromechanical Systems, Transducers 99 10th International Conference on Solid-State Sensors and Actuators, Sendai Fitzgerald, A., M., Dauskardt, R., H., Kenny, T., W. 1999: 928-931
  • High-resolution measurement of crack growth in micromachined single crystal silicon Fitzgerald, A., M., Dauskardt, R., H., Kenny, T., W. 1999
  • Adhesion and Progressive Debonding of Polymer/Metal Interfaces: Effects of Temperature and Environment Kook, S.-Y., Kirtikar, A., Dauskardt, R., H. 1999
  • Effect of Nitrogen on Adhesion of the Ta/SiO2 Interface Lane, M., Krishna, N., Hashim, I., Dauskardt, R., H. 1999
  • Fracture Toughness of Plasma-Etched Single Crystal Silicon and Implications for MEMS Design in Symposium on Microelectromechanical Systems, Transducers 99 10th International Conference on Solid-State Sensors and Actuators Fitzgerald, A., M., Dauskardt, R., H., Kenny, T., W. 1999: 928-931
  • The effects of environment and fatigue on the adhesion and subcritical debonding of dielectric polymers Symposium O: Low-Dielectric Constant Materials at the 1999 MRS Spring Meeting Snodgrass, J. M., Pantelidis, D., Bravman, J. C., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 1999: 123–128
  • Effect of nitrogen content on interfacial adhesion of the Ta/SiO2 interface Symposium N on Advanced Interconnects and Contacts, at the 1999 MRS Spring Meeting Lane, M., Dauskardt, R., Krishna, N., Hashim, I. MATERIALS RESEARCH SOCIETY. 1999: 281–286
  • Reliability of electroless processed thin layered solder joints Materials Reliability in Microelectronics IX Symposium at the 1999 MRS Spring Meeting Wang, L. C., Mei, Z., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 1999: 3–8
  • Adhesion and progressive debonding of polymer/metal interfaces: Effects of temperature and environment Materials Reliability in Microelectronics IX Symposium at the 1999 MRS Spring Meeting Kook, S. Y., Kirtikar, A., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 1999: 263–268
  • Subcritical growth of microstructurally small cracks in silicon nitride ceramics 3rd Engineering Foundation International Conference on Small Fatigue Cracks Haubensak, F. G., BHATNAGAR, A., Dauskardt, R. H. ELSEVIER SCIENCE BV. 1999: 271–282
  • Ion irradiation effects for two pyrochlore compositions: Gd2Ti2O7 and Gd2Zr2O7 Symposium on Microstructural Processes in Irradiated Materials, at the 1998 Fall MRS Meeting Wang, S. X., Wang, L. M., Ewing, R. C., Kutty, K. V. MATERIALS RESEARCH SOCIETY. 1999: 355–360
  • Adhesion and reliability of polymer/inorganic interfaces JOURNAL OF ELECTRONIC PACKAGING Kook, S. Y., Snodgrass, J. M., Kirtikar, A., Dauskardt, R. H. 1998; 120 (4): 328-335
  • Adhesion and reliability of interfaces in cemented total joint arthroplasties JOURNAL OF ORTHOPAEDIC RESEARCH Ohashi, K. L., Romero, A. C., McGowan, P. D., Maloney, W. J., Dauskardt, R. H. 1998; 16 (6): 705-714

    Abstract

    Debonding of the prosthetic/polymethylmethacrylate interface has been implicated in the initial failure process of cemented total hip arthroplasties. However, little quantitative understanding of the debonding process, as well as of the optimum interface morphology for enhanced resistance to debonding, exists. Accordingly, a fracture-mechanics approach has been used in which adhesion at the interface is characterized in terms of the interface fracture energy, G (J/m2), and shown to be a strong function of the morphology, debonding length, and loading mode of the interface. Double-cantilever-beam and four-point-flexure fracture-mechanics samples containing four clinically relevant prosthetic surface preparations were prepared to survey a range of interface roughness and loading modes. Adhesion at the interface could not be characterized with a single-valued material property but was found to exhibit resistance-curve behavior in which resistance to debonding increased with both the initial debond extension and the roughness of the interface. Values of debonding initiation, Go, were relatively insensitive to the roughness of the surface and the loading mode, whereas steady-state fracture resistance of the interface, Gss, increased significantly with the roughness and shear loading of the interface. These quantitative results suggest that debonding of the prosthetic/polymethylmethacrylate interface may be primarily attributed to surface interactions such as interlocking and the pullout of rough asperities that occur behind the debond tip. A simple mechanics analysis of such interactions was performed and revealed increases in the fracture resistance of the interface that were consistent with experimentally measured values.

    View details for Web of Science ID 000077786300011

    View details for PubMedID 9877395

  • Adhesion and debonding of multi-layer thin film structures Special Session on Nanomechanics and Nanofracture, at the 9th International Conference on Fracture Dauskardt, R., Lane, M., Ma, Q., Krishna, N. PERGAMON-ELSEVIER SCIENCE LTD. 1998: 141–62
  • Debonding of interfaces in multilayer interconnect structures Symposium on Advanced Interconnects and Contact Materials and Processes for Future Integrated Circuits Lane, M., Ni, W., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 1998: 141–141
  • Adhesion and Progressive Debonding of Polymer/Metal Interfaces in Microelectronic Applications Kook, S., -Y., Kirtikar, A., Dauskardt, R., H. 1998
  • Effect of a Photochemically Activated Adhesion Promoter on the Adhesion of PMMA/Si Interfaces Lin, J., Snodgress, J., M., Dauskardt, R, H. 1998
  • Subcritical Crack-Growth Behavior in Materials Under Cyclic Loads: Effect of Hydrodynamic Pressure Created by Viscous Environments Journal of the Mechanics and Physics of Solids Yi, K., S., Cox, B., N., Dauskardt, R., H. 1998; 9 (47): 1843-1871
  • Effects of Interface Nonplanarity on the Interface Fracture Energy on the TiN/SiO2 System Lane, M., Ni, W., Dauskardt, R., H., Ma, Q., Fujimoto, H., Krishna, N. 1998
  • Quantitative Assessment of Interface Fracture at Bone Cement/Metal Prosthetic Interfaces in Total Hip Arthroplasties Journal of Orthopedic Research Ohashi, K., L., Romero, A., C., McGrowan, P., W., Maloney, W., J., Dauskardt, R., H. 1998; 6 (16): 705-714
  • Adhesion and Subcritical Debonding of Interfaces for Die Attach Applications Snodgrass, J., M., Dauskardt, R., H. 1998
  • Fracture and Sub-Critical Crack Growth Behavior of Micromachined Single Crystal Silicon Structures in Symposium on Microelectromechanical Systems, 1998 ASME International Mechanical Engineering Congress &Exopsition Fitzgerald, A., M., Iyer, R., Suryanarayanan, Dauskardt, R., H., Kenny, T., W. 1998: 395-399
  • Adhesion and subcritical debonding of polymer interfaces for microelectronic packaging 10th Symposium on Electronic Packaging Materials Science at MRS Spring Meeting Snodgrass, J. M., Hotchkiss, G., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 1998: 37–43
  • Effects of interface nonplanarity on the interface fracture energy of the TiN/SiO2 system Symposium on Thin-Films - Stresses and Mechanical Properties VII at the MRS Fall Meeting Lane, M., Ni, W., Dauskardt, R., Ma, Q., Fujimoto, H., Krishna, N. MATERIALS RESEARCH SOCIETY. 1998: 357–362
  • Observations of low cycle fatigue of Al thin films for MEMS applications Symposium on Microelectromechanical Structures for Materials Research Cornella, G., Vinci, R. P., Iyer, R. S., Dauskardt, R. H., Bravman, J. C. MATERIALS RESEARCH SOCIETY. 1998: 81–86
  • New adhesion measurement technique for coated cutting tool materials INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS Mroz, J., Dauskardt, R. H., Schleinkofer, U. 1998; 16 (4-6): 395-402
  • Mechanical properties of carbonated apatite bone mineral substitute: strength, fracture and fatigue behaviour JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE Morgan, E. F., Yetkinler, D. N., Constantz, B. R., Dauskardt, R. H. 1997; 8 (9): 559-570

    Abstract

    The synthesis and properties of carbonated apatite materials have received considerable attention due to their importance for medical and dental applications. Such apatites closely resemble the mineral phase of bone, exhibiting superior osteoconductive and osteogenic properties. When formed at physiological temperature they present significant potential for bone repair and fracture fixation. The present study investigates the mechanical properties of a carbonated apatite cancellous bone cement. Flexural strength was measured in three and four point bending, and the fracture toughness and fatigue crack-growth behaviour was measured using chevron and disc-shaped compact tension specimens. The average flexural strength was found to be approximately 0.468 MPa, and the fracture toughness was approximately 0.14 MPa radical m. Fatigue crack-growth rates exhibited a power law dependence on the applied stress intensity range with a crack growth exponent m=17. The fatigue threshold value was found to be approximately 0.085 MPa radical m. The mechanical properties exhibited by the carbonated apatite were found to be similar to those of other brittle cellular foams. Toughness values and fatigue crack-growth thresholds were compared to other brittle foams, bone and ceramic materials. Implications for structural integrity and longer term reliability are discussed.

    View details for Web of Science ID A1997XV77100006

    View details for PubMedID 15348708

  • Reliability of PMMA bone cement fixation: fracture and fatigue crack-growth behaviour JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE Nguyen, N. C., Maloney, W. J., Dauskardt, R. H. 1997; 8 (8): 473-483

    Abstract

    Fracture mechanics tests were performed to characterize the fracture toughness and fatigue crack-growth behaviour of polymethylmethacrylate (PMMA) bone cement, commonly used in joint replacement surgery. Compact tension specimens of various thicknesses were prepared and tested in both air and Ringer's solution. Contrary to previous reports citing toughness as a single valued parameter, the PMMA was found to exhibit resistance-curve behaviour with a plateau toughness of approximately 0.6 MPa m1/2 in air, and approximately 2.0 MPa m1/2 in Ringer's solution. The increased toughness in Ringer's solution is thought to arise from the plasticizing effect of the environment. Under cyclic loads, the material displayed true mechanical fatigue failure in both environments; fatigue crack-growth rates, da/dN, were measured over the range approximately 10(-10) to 10(-6) m/cycle and found to display a power-law dependence on the stress intensity range, DeltaK. The cement was found to be more resistant to fatigue-crack propagation in Ringer's solution than in air. Wear debris was observed on the fatigue fracture surfaces, particularly those produced in air. These findings and the validity of using a linear-elastic fracture mechanics approach for viscoelastic materials are discussed in the context of providing more reliable and fracture-resistant cemented joints.

    View details for Web of Science ID A1997XQ16600003

    View details for PubMedID 15348713

  • Subcritical crack growth in glasses under cyclic loads: Effect of hydrodynamic pressure in aqueous environments ACTA MATERIALIA Yi, K. S., Dill, S. J., Dauskardt, R. H. 1997; 45 (7): 2671-2684
  • Fracture and fatigue crack-growth behavior of single crystal NiAl SCRIPTA MATERIALIA Flores, K. M., Dauskardt, R. H. 1997; 36 (12): 1377-1382
  • Subcritical crack-growth behavior of borosilicate glass under cyclic loads: Evidence of a mechanical fatigue effect JOURNAL OF THE AMERICAN CERAMIC SOCIETY Dill, S. J., Bennison, S. J., Dauskardt, R. H. 1997; 80 (3): 773-776
  • Microstructural mechanisms of cyclic fatigue-crack propagation in grain-bridging ceramics CERAMICS INTERNATIONAL Gilbert, C. J., Dauskardt, R. H., Ritchie, R. O. 1997; 23 (5): 413-418
  • Adhesion measurement of interfaces in multilayer interconnect structures Symposium on Materials Reliability in Microelectronics, at the 1997 MRS Spring Meeting Ma, Q., Bumgarner, J., Fujimoto, H., Lane, M., Dauskardt, R. H. MATERIALS RESEARCH SOCIETY. 1997: 3–14
  • Subcritical Crack-Growth Behavior in Glasses and Ceramics: Effect of Hydrodynamic Pressures in Aqueous Environments Acta Metallurgicaet Materialia Yi, K., S., Dill, S., J., Dauskardt, R., H. 1997; 7 (45): 2671-2684
  • Subcritical Crack-Growth Behavior of Borosilicate Glass under Cyclic Loads: Evidence of a Mechanical Fatigue Effect Journal of the American Ceramics Society Dill, S., J., Bennison, S., J., Dauskardt, R., H. 1997; 3 (80): 773-76
  • Microstructural Mechanisms of Cyclic Fatigue-Crack Propagation in Grain Bridging Ceramics Ceramics International Gilbert, C., J., Dauskardt, R., H., Ritchie, R., O. 1997; 23: 413-418
  • Mechanical Properties of Carbonated Hydroxyapatite Bone Mineral Substitute: Strength, Fracture and Fatigue Behavior Journal of Materials Science: Materials in Medicine Morgan, E., Yetkinler, D., N, Constantz, B., R, Dauskardt, R., H 1997; 9 (8): 559-570
  • Adhesion Measurement of Interfaces in Multilayer Interconnect Structures Ma, Q., Bumgarner, J., Fujimoto, H., Lane, M., Dauskardt, R., H. 1997
  • Reliability of PMMA Bone Cement Fixation: Fracture and Fatigue Crack-Growth Behavior Journal of Materials Science: Materials in Medicine Nguyen, N., C., Maloney, W., J., Dauskardt, R., H. 1997; 8 (8): 473-483
  • Adhesion and Reliability of Polymer/Inorganic Interfaces in Microelectronic Applications Snodgrass, J., M., Kook, S., -Y., Kirtikar, A., Dauskardt, R., H. 1997
  • Adhesion and progressive delamination of polymer/metal interfaces Symposium on High Cycle Fatigue of Structural Materials in Honor of Professor Paul C Paris, Held During Materials Week 97 Dauskardt, R. H., Kook, S. Y., Kirtikar, A., Ohashi, K. L. MINERALS, METALS & MATERIALS SOC. 1997: 479–498
  • Quantitative stress mapping in alumina composites by optical fluorescence imaging ACTA MATERIALIA Dauskardt, R. H., Ager, J. W. 1996; 44 (2): 625-641
  • Adhesion and Reliability of Interfaces in Cemented Total Joint Arthroplasties Ohashi, K., L., Romero, A., C., McGowan, P., D., Maloney, W., J., Dauskardt, R., H. 1996
  • BEHAVIOR OF CYCLIC FATIGUE CRACKS IN MONOLITHIC SILICON-NITRIDE JOURNAL OF THE AMERICAN CERAMIC SOCIETY Gilbert, C. J., Dauskardt, R. H., Ritchie, R. O. 1995; 78 (9): 2291-2300
  • FRACTURE OF SYNTHETIC DIAMOND JOURNAL OF APPLIED PHYSICS DRORY, M. D., Dauskardt, R. H., Kant, A., Ritchie, R. O. 1995; 78 (5): 3083-3088
  • GRAIN-SIZE EFFECTS ON CYCLIC FATIGUE AND CRACK-GROWTH RESISTANCE BEHAVIOR OF PARTIALLY-STABILIZED ZIRCONIA JOURNAL OF MATERIALS SCIENCE Hoffman, M. J., Mai, Y. W., Dauskardt, R. H., Ager, J., Ritchie, R. O. 1995; 30 (13): 3291-3299
  • MICROSTRUCTURAL DAMAGE AND FRACTURE PROCESSES IN A COMPOSITE SOLID ROCKET PROPELLANT JOURNAL OF SPACECRAFT AND ROCKETS BENCHER, C. D., Dauskardt, R. H., Ritchie, R. O. 1995; 32 (2): 328-334
  • CYCLIC FATIGUE IN MONOLITHIC ALUMINA - MECHANISMS FOR CRACK ADVANCE PROMOTED BY FRICTIONAL WEAR OF GRAIN BRIDGES JOURNAL OF MATERIALS SCIENCE Gilbert, C. J., PETRANY, R. N., Ritchie, R. O., Dauskardt, R. H., Steinbrech, R. W. 1995; 30 (3): 643-654
  • Fracture of Synthetic Diamond Journal of Applied Physics Drory, M., D., Dauskardt, R., H., Kant, A., Ritchie, R., O. 1995; 5 (78): 3083-88
  • Fracture, fatigue and indentation behavior of pyrolytic carbon for biomedical applications Symposium on Mechanical Behavior of Diamond and Other Forms of Carbon Ritchie, R. O., Dauskardt, R. H., Gerberich, W. W., Strojny, A., Lilleodden, E. MATERIALS RESEARCH SOC. 1995: 229–254
  • Quantitative measurement of interface fracture energy in multi-layer thin film structures 5th Symposium on Materials Reliability in Microelectronics, at the 1995 MRS Spring Meeting Ma, Q., Fujimoto, H., Flinn, P., Jain, V., AdibiRizi, F., Moghadam, F., Dauskardt, R. H. MATERIALS RESEARCH SOC. 1995: 91–96
  • Grain Size Effects on Cyclic Fatigue and Crack-Growth Resistance Behavior of Partially Stabilized Zirconia Journal of Materials Science Hoffman, M., J., Mai, Y., W., Dauskardt, R., H., Ager, J., Ritchie, R., O. 1995; 30: 3291-99
  • Quantitative Measurement of Interface Fracture Energy in Multi-Layer Thin Film Structures Dauskardt, R., H., Ma, Q., Fujimoto, H., Flinn, P., Jain, V., Adibi-Rizi, F. 1995
  • Microstructural Mechanisms of Cyclic Fatigue-Crack Propagation in Grain Bridging Ceramics Gilbert, C., J., Dauskardt, R., H., Ritchie, R., O. 1995
  • Mechanics and Mechanisms of Crack Growth At on Near Interfaces in Cemented Load Bearing Prosthetics, Dauskardt, R., H., Nguyen, N., Christine, Maloney, W., J. 1995
  • Cyclic Fatigue in Monolithic Alumina: Mechanisms for Crack Advance Promoted by Frictional Wear of Grain Bridges Journal of Materials Science Gilbert, C., J., Petrany, R., N., Dauskardt, R., H., Steinbrech, R., W., Ritchie, R., O. 1995; 30: 643-54
  • Cyclic Fatigue and Fracture in Pyrolytic Carbon-Coated Graphite Mechanical Heart-Valve Prostheses: Role of Small Cracks in Life Prediction Journal of Biomechanical Materials Research Dauskardt, R., H., Ritchie, R., O., Takemoto, J., K., Brendzel, A., M. 1995; 5 (29): 676-678
  • Microstructural Damage and Fracture Processes in a Composite Solid Rocket Propellant Journal of Spacecrafts and Rockets Bencher, C., D., Dauskardt, R., H., Ritchie, R., O. 1995; 2 (32): 328-34
  • Behavior of Cyclic Fatigue Cracks in Monolithic Silicon Nitride Journal of the American Ceramics Society Gilbert, C., J., Dauskardt, R., H., Ritchie, R., O. 1995; 9 (78): 2291-300
  • CYCLIC FATIGUE BEHAVIOR AND FRACTURE-TOUGHNESS OF SILICON-NITRIDE CERAMICS SINTERED WITH RARE-EARTH-OXIDES ACTA METALLURGICA ET MATERIALIA CORNELISSEN, B. E., Dauskardt, R. H., Ritchie, R. O., Thomas, G. 1994; 42 (9): 3055-3064
  • CYCLIC FATIGUE AND FRACTURE IN PYROLYTIC CARBON-COATED GRAPHITE MECHANICAL HEART-VALVE PROSTHESES - ROLE OF SMALL CRACKS IN LIFE PREDICTION JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Dauskardt, R. H., Ritchie, R. O., TAKEMOTO, J. K., Brendzel, A. M. 1994; 28 (7): 791-804

    Abstract

    A fracture-mechanics based study has performed to characterize the fracture toughness and rates of cyclic fatigue-crack growth of incipient flaws in prosthetic heart-valve components made of pyrolytic carbon-coated graphite. Such data are required to predict the safe structural lifetime of mechanical heart-valve prostheses using damage-tolerant analysis. Unlike previous studies where fatigue-crack propagation data were obtained using through-thickness, long cracks (approximately 2-20 mm long), growing in conventional (e.g., compact-tension) samples, experiments were performed on physically small cracks (approximately 100-600 microns long), initiated on the surface of the pyrolytic-carbon coating to simulate reality. Small-crack toughness results were found to agree closely with those measured conventionally with long cracks. However, similar to well-known observations in metal fatigue, it was found that based on the usual computations of the applied (far-field) driving force in terms of the maximum stress intensity, Kmax, small fatigue cracks grew at rates that exceeded those of long cracks at the same applied stress intensity, and displayed a negative dependency on Kmax; moreover, they grew at applied stress intensities less than the fatigue threshold value, below which long cracks are presumed dormant. To resolve this apparent discrepancy, it is shown that long and small crack results can be normalized, provided growth rates are characterized in terms of the total (near-tip) stress intensity (incorporating, for example, the effect of residual stress); with this achieved, in principle, either form of data can be used for life prediction of implant devices. Inspection of the long and small crack results reveals extensive scatter inherent in both forms of growth-rate data for the pyrolytic-carbon material.

    View details for Web of Science ID A1994NR13500005

    View details for PubMedID 8083247

  • FATIGUE-CRACK PROPAGATION BEHAVIOR IN MONOLITHIC AND COMPOSITE CERAMICS AND INTERMETALLICS MATERIALS SCIENCE Ritchie, R. O., Dauskardt, R. H., Rao, K. T. 1994; 30 (3): 277-300
  • BACK-FACE STRAIN COMPLIANCE AND ELECTRICAL-POTENTIAL CRACK LENGTH CALIBRATIONS FOR THE DISK-SHAPED COMPACT-TENSION DC(T) SPECIMEN JOURNAL OF TESTING AND EVALUATION Gilbert, C. J., McNaney, J. M., Dauskardt, R. H., Ritchie, R. O. 1994; 22 (2): 117-120
  • High temperature fatigue-crack growth experiments in ceramics and ceramic-matrix composites 1994 SEM Spring Conference on Experimental Mechanics Dauskardt, R. H., Mitchell, M. R. SOC EXPERIMENTAL MECHANICS INC. 1994: 685–690
  • ON THE STRENGTH AND TOUGHNESS OF STRUCTURAL CERAMICS BONDED TO METALS 3rd IUMRS International Conference on Advanced Materials (ICAM) Ritchie, R. O., Cannon, R. M., Dalgleish, B. J., Dauskardt, R. H., McNaney, J. M. ELSEVIER SCIENCE BV. 1994: 409–12
  • FATIGUE-CRACK PROPAGATION BEHAVIOR IN MONOLITHIC AND COMPOSITE CERAMICS AND INTERMETALLICS 8th International Conference on Fracture (ICF8) Ritchie, R. O., Dauskardt, R. H., Rao, K. T. PERGAMON PRESS LTD. 1994: 277–317
  • FATIGUE-CRACK PROPAGATION BEHAVIOR IN CERAMIC MATERIALS 3rd IUMRS International Conference on Advanced Materials (ICAM) Ritchie, R. O., Dauskardt, R. H. ELSEVIER SCIENCE BV. 1994: 359–64
  • Fatigue-Crack Propagation Behavior in Monolithic and Composite Ceramics and Intermetallics Materials Science Ritchie, R., O., Dauskardt, R., H., Rao, K., T. Venkateswara 1994; 3 (30): 277-300
  • Fatigue-Crack Propagation Behavior in Monolithic and Composite Ceramics and Intermetallics Ritchie, R., O., Dauskardt, R., H., Rao, K., T. Venkateswara 1994
  • Cyclic Fatigue Behavior and Fracture Toughness of Silicon Nitride Sintered With Rare-Earth Oxides Acta Metallurgica et Materialia Cornelissen, B., E., Dauskardt, R., H., Ritchie, R., O., Thomas, G. 1994; 9 (42): 3055-3064
  • Cyclic Fatigue-Crack Growth in Si3N4 Ceramics Tailoring of High Temperature Properties of Si3N4 Ceramics Dauskardt, R., H. Kluwer Academic Publishers, Dordrecht. 1994: 365–378
  • Fatigue-Crack Propagation Behavior in Monolithic and Composite Ceramics and Intermetallics Ritchie, R., O., Dauskardt, R., H., Rao, K., T. Venkateswara edited by Panasyuk, V., V., Rao, P., Pama, Taplin, D., M. R. 1994
  • Back-Face Strain Compliance and Electrical-Potential Crack Length Calibrations for the Disk-Shaped Compact-Tension DC(T) Specimen Journal of Testing and Evaluation Gilbert, C., J., McNaney, J., M., Dauskardt, R., H., Ritchie, R., O. 1994; 3: 117-120
  • Fatigue-Crack Propagation Behavior in Ceramic Materials. Transactions of the Materials Research Society of Japan Ritchie, R., O., Dauskardt, R., H. 1994; 14A: 359-364
  • Crack Path and Fracture Energies in Ceramic-Metal Sandwich Geometries Journal of the American Ceramic Society Cannon, R., M., Dalgleish, B., J., Dauskardt, R., H., McNaney, J., M., Ritchie, R., O. 1994; 76
  • On the Strength and Toughness of Structural Ceramics Bonded to Metals Transactions of the Materials Research Society of Japan Ritchie, R., O., Cannon, R., M., Dalgleish, B., J., Dauskardt, R., H., McNaney, J., M. 1994; 14A: 409-412
  • High Temperature Fatigue-Crack Growth Experiments in Ceramics and Ceramic-Matrix Composites Dauskardt, R., H., Mitchell, M., R. 1994
  • CYCLIC FATIGUE-CRACK GROWTH IN SI3N4-CERAMICS NATO Advanced Research Workshop on Tailoring of High Temperature Properties of Si3N4 Ceramics Dauskardt, R. H. SPRINGER. 1994: 365–378
  • FATIGUE OF ADVANCED MATERIALS .2. ADVANCED MATERIALS & PROCESSES Dauskardt, R. H., Ritchie, R. O., Cox, B. N. 1993; 144 (2): 30-35
  • MECHANICS AND MECHANISMS OF CRACK-GROWTH AT OR NEAR CERAMIC-METAL INTERFACES - INTERFACE ENGINEERING STRATEGIES FOR PROMOTING TOUGHNESS WORKSHOP ON GRAIN BOUNDARY AND INTERFACE PHENOMENA IN THE HIGH TEMPERATURE PLASTICITY OF SOLIDS Ritchie, R. O., Cannon, R. M., Dalgleish, B. J., Dauskardt, R. H., McNaney, J. M. ELSEVIER SCIENCE SA. 1993: 221–35
  • FATIGUE OF ADVANCED MATERIALS .1. ADVANCED MATERIALS & PROCESSES Dauskardt, R. H., Ritchie, R. O., Cox, B. N. 1993; 144 (1): 26-?
  • CYCLIC FATIGUE-CRACK PROPAGATION IN A SILICON-CARBIDE WHISKER-REINFORCED ALUMINA COMPOSITE - ROLE OF LOAD RATIO JOURNAL OF MATERIALS SCIENCE Dauskardt, R. H., Dalgleish, B. J., Yao, D., Ritchie, R. O., Becher, P. F. 1993; 28 (12): 3258-3266
  • Cyclic Fatigue-Crack Growth in Grain Bridging Ceramics Engineering Materials and Technology Dauskardt, R., H. 1993; 115: 244-251
  • FATIGUE-CRACK PROPAGATION IN ADVANCED MATERIALS 5th International Conference on Fatigue and Fatigue Thresholds Ritchie, R. O., Venkateswara, K. T., Dauskardt, R. H. ENGINEERING MATERIALS ADVISORY SERVICES LTD. 1993: 1899–1918
  • ROLE OF SMALL CRACKS IN THE STRUCTURAL INTEGRITY OF PYROLYTIC CARBON HEART-VALVE PROSTHESES 6th International Symposium on Ceramics in Medicine Dauskardt, R. H., Ritchie, R. O., Brendzel, A. M. BUTTERWORTH-HEINEMANN. 1993: 229–236
  • Matrix and Interfacial Fatigue-Crack Growth in Advanced Structural Materials Ritchie, R., O., Dauskardt, R., H., Rao, K, T. Venkateswara 1993
  • Effect of Encapsulation Processing on Toughness and Crack Growth Behavior of Silicon Carbide/Polymethacrylate Particulate Composites Journal of Material Science Sheu, C., Dauskardt, R., H., Jonghe, L., C. De 1993; 28: 2196-2206
  • Fatigue-Crack Propagation in Advanced Materials Ritchie, R., O., Rao, K., T. Venkateswara, Dauskardt, R., H. edited by Bailon, J. -P., Dickson, J., I. 1993
  • Cyclic Fatigue-Crack Propagation in a Silicon Carbide Whisker-Reinforced Alumina Composite: Role of Load Ratio Journal of Materials Science Dauskardt, R., H., Dalgleish, B., J., Yao, D., Ritchie, R., O., Becher, P., F. 1993; 28: 3258-3266
  • A Frictional-Wear Mechanism For Fatigue-Crack Growth in Grain Bridging Ceramics Acta Metallurgicaet Materialia Dauskardt, R., H. 1993; 9 (41): 2765-2781
  • Fracture and Fatigue-Crack Propagation Behavior in High-Temperature Ceramics and Intermetallics Ritchie, R., O., Rao, K., T. Venkateswara, Dauskardt, R., H. edited by Kishi, T., Takada, N., Kagawa, Y. 1993
  • Pyrolytic Carbon Coatings An Introduction to Bioceramics Dauskardt, R., H., Ritchie, R., O. World Scientific Publishing Co.. 1993: 261–279
  • Fatigue of Advanced Materials: Part II Advanced Materials and Processes Dauskardt, R., H., Ritchie, R., O., Cox, B., N. 1993; 8 (144): 30-35
  • Mechanics and Mechanisms of Crack Growth at or near Ceramic-Metal Interfaces: Interface Engineering Strategies for Promoting Toughness Materials Science and Engineering A Ritchie, R., O., Cannon, R., M., Dalgleish, B., J., Dauskardt, R., H., McNaney, J., M. 1993; A166: 221-235
  • Role of Small Cracks in the Structural Integrity of Pyrolytic Carbon Heart-Valve Prostheses Dauskardt, R., H., Ritchie, R., O., Brendzel, A., M. edited by Ducheyne, P., Christiansen, D. 1993
  • A Review of the Mechanics and Mechanisms of Cyclic Fatigue-Crack Propagation in Transformation-Toughened Zirconia Ceramics Hoffman, M., J., Dauskardt, R., H., Mai, Y. -W., Ritchie, R., O. edited by Badwal, S., P. S., Bannister, M., J., Hannink, R., H. J. 1993
  • Fatigue of Advanced Materials: Part I Advanced Materials and Processes Dauskardt, R., H., Ritchie, R., O., Cox, B., N. 1993; 7 (144): 26-31
  • CYCLIC FATIGUE-CRACK GROWTH IN A SIC-WHISKER-REINFORCED ALUMINA CERAMIC COMPOSITE - LONG-CRACK AND SMALL-CRACK BEHAVIOR JOURNAL OF THE AMERICAN CERAMIC SOCIETY Dauskardt, R. H., James, M. R., PORTER, J. R., Ritchie, R. O. 1992; 75 (4): 759-771
  • On the Fractography of Overload, Stress Corrosion and Cyclic Fatigue Failures in Pyrolytic-Carbon Materials used in Prosthetic Heart-Valve Devices Journal of Biomedical Materials Research Ritchie, R., O., Dauskardt, R., H., Pennisi, F., J. 1992; 26: 69-76
  • ON THE FRACTOGRAPHY OF OVERLOAD, STRESS-CORROSION, AND CYCLIC FATIGUE FAILURES IN PYROLYTIC-CARBON MATERIALS USED IN PROSTHETIC HEART-VALVE DEVICES JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Ritchie, R. O., Dauskardt, R. H., PENNISI, F. J. 1992; 26 (1): 69-76

    Abstract

    A scanning electron microscopy study is reported of the nature and morphology of fracture surfaces in pyrocarbons commonly used for the manufacture of mechanical heart-valve prostheses. Specifically, silicon-alloyed low-temperature-isotropic (LTI)-pyrolytic carbon is examined, both as a coating on graphite and as a monolithic material, following overload, stress corrosion (static fatigue), and cyclic fatigue failures in a simulated physiological environment of 37 degrees C Ringer's solution. It is found that, in contrast to most metallic materials yet in keeping with many ceramics, there are no distinct fracture morphologies in pyro-carbons which are characteristic of a specific mode of loading; fracture surfaces appear to be identical for both catastrophic and subcritical crack growth under either sustained or cyclic loading. We conclude that caution should be used in assigning the likely cause of failure of pyrolytic carbon heart-valve components using fractographic examination.

    View details for Web of Science ID A1992GV29800006

    View details for PubMedID 1577836

  • Cyclic Fatigue-Crack Growth in Pyrolytic-Carbon Materials: Implications for Prosthetic Heart-Valve Devices Dauskardt, R., H., Ritchie, R., O. 1992
  • Cyclic Fatigue-Crack Growth in SiC-Whisker-Reinforced Alumina Composite: Long and Small-Crack Behavior Journal of the American Ceramic Society Dauskardt, R., H., James, M., R., Porter, J., R., Ritchie, R., O. 1992; 75: 759-71
  • Small-Crack Behavior and Safety Critical Design Criteria for Cyclic Fatigue in Mg-PSZ, Cyclic Deformation, Fracture and Non-Destructive Evaluation of Advanced Materials Steffen, A., A., Dauskardt, R., H., Ritchie, R., O. American Society for Testing and Materials, Philadelphia. 1992: 69–81
  • CYCLIC FATIGUE OF CERAMICS - A FRACTURE-MECHANICS APPROACH TO SUBCRITICAL CRACK-GROWTH AND LIFE PREDICTION NIPPON SERAMIKKUSU KYOKAI GAKUJUTSU RONBUNSHI-JOURNAL OF THE CERAMIC SOCIETY OF JAPAN Ritchie, R. O., Dauskardt, R. H. 1991; 99 (10): 1047-1062
  • CYCLIC FATIGUE-CRACK PROPAGATION ALONG CERAMIC METAL INTERFACES ACTA METALLURGICA ET MATERIALIA Cannon, R. M., Dalgleish, B. J., Dauskardt, R. H., Oh, T. S., Ritchie, R. O. 1991; 39 (9): 2145-2156
  • CYCLIC FATIGUE LIFE AND CRACK-GROWTH BEHAVIOR OF MICROSTRUCTURALLY SMALL CRACKS IN MAGNESIA-PARTIALLY-STABILIZED ZIRCONIA CERAMICS JOURNAL OF THE AMERICAN CERAMIC SOCIETY STEFFEN, A. A., Dauskardt, R. H., Ritchie, R. O. 1991; 74 (6): 1259-1268
  • Cyclic Fatigue of Ceramics Dauskardt, R., H., Ritchie, R., O. edited by Cox, B., N., Dauskardt, R., H., Ritchie, R., O. 1991
  • Cyclic Fatigue-Crack Propagation along Ceramic/Metal Interfaces Acta Metallurgica et Materialia Cannon, R., M., Dalgleish, B., J., Dauskardt, R., H., Oh, T., S., Ritchie, R., O. 1991; 9 (39): 2145-2156
  • Cyclic Fatigue Life and Crack- Growth Behavior of Microstructurally-Small Cracks in Mg-PSZ Ceramics Journal of the American Ceramic Society Steffen, A., A., Dauskardt, R., H., Ritchie, R., O. 1991; 6 (74): 1259-68
  • Cyclic Fatigue-Crack Propagation in Ceramics and Ceramic Composites Dauskardt, R., H., Ritchie, R., O. 1991
  • Ceramic/Metal Interfaces: Monotonic and Cyclic Fracture Resistance Cannon, R., M., Dalgleish, B., J., Dauskardt, R., H., Fisher, R., M., Oh, T., S., Ritchie, R., O. edited by Dauskardt, R., H, Ritchie, R., O. 1991
  • Cyclic Fatigue of Ceramics: A Fracture Mechanics Approach to Subcritical Crack Growth and Life Prediction Journal of the Ceramic Society of Japan Ritchie, R., O., Dauskardt, R., H. 1991; 10 (99): 1047-1062
  • TRANSIENT SUBCRITICAL CRACK-GROWTH BEHAVIOR IN TRANSFORMATION-TOUGHENED CERAMICS ACTA METALLURGICA ET MATERIALIA Dauskardt, R. H., Carter, W. C., Veirs, D. K., Ritchie, R. O. 1990; 38 (11): 2327-2336
  • CRACK-TIP TRANSFORMATION ZONES IN TOUGHENED ZIRCONIA JOURNAL OF THE AMERICAN CERAMIC SOCIETY Marshall, D. B., Shaw, M. C., Dauskardt, R. H., Ritchie, R. O., Readey, M. J., HEUER, A. H. 1990; 73 (9): 2659-2666
  • CYCLIC FATIGUE-CRACK GROWTH-BEHAVIOR OF SHORT CRACKS IN SIC-REINFORCED LITHIUM ALUMINOSILICATE GLASS-CERAMIC COMPOSITE JOURNAL OF MATERIALS SCIENCE LETTERS LUH, E. Y., Dauskardt, R. H., Ritchie, R. O. 1990; 9 (6): 719-725
  • CYCLIC FATIGUE-CRACK PROPAGATION IN MAGNESIA-PARTIALLY-STABILIZED ZIRCONIA CERAMICS JOURNAL OF THE AMERICAN CERAMIC SOCIETY Dauskardt, R. H., Marshall, D. B., Ritchie, R. O. 1990; 73 (4): 893-903
  • ON THE INTERPRETATION OF THE FRACTAL CHARACTER OF FRACTURE SURFACES ACTA METALLURGICA ET MATERIALIA Dauskardt, R. H., HAUBENSAK, F., Ritchie, R. O. 1990; 38 (2): 143-159
  • CYCLIC FATIGUE-CRACK PROPAGATION, STRESS-CORROSION, AND FRACTURE-TOUGHNESS BEHAVIOR IN PYROLYTIC CARBON-COATED GRAPHITE FOR PROSTHETIC HEART-VALVE APPLICATIONS JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Ritchie, R. O., Dauskardt, R. H., Yu, W. K., Brendzel, A. M. 1990; 24 (2): 189-206

    Abstract

    Fracture-mechanics tests were performed to characterize the cyclic fatigue, stress-corrosion cracking, and fracture-toughness behavior of a pyrolytic carbon-coated graphite composite material used in the manufacture of cardiac valve prostheses. Testing was carried out using compact tension C(T) samples containing "atomically" sharp precracks, both in room-temperature air and principally in a simulated physiological environment of 37 degrees C Ringer's lactate solution. Under sustained (monotonic) loads, the composite exhibited resistance-curve behavior, with a fracture toughness (KIc) between 1.1 and 1.9 MPa square root of m, and subcritical stress-corrosion crack velocities (da/dt) which were a function of the stress intensity K raised to the 74th power (over the range approximately 10(-9) to over 10(-5) m/s). More importantly, contrary to common perception, under cyclic loading conditions the composite was found to display true (cyclic) fatigue failure in both environments; fatigue-crack growth rates (da/dN) were seen to be a function of the 19th power of the stress-intensity range delta K (over the range approximately 10(-11) to over 10(-8) m/cycle). As subcritical crack velocities under cyclic loading were found to be many orders of magnitude faster than those measured under equivalent monotonic loads and to occur at typically 45% lower stress-intensity levels, cyclic fatigue in pyrolytic carbon-coated graphite is reasoned to be a vital consideration in the design and life-prediction procedures of prosthetic devices manufactured from this material.

    View details for Web of Science ID A1990CM36000005

    View details for PubMedID 2329114

  • Cyclic Fatigue-Crack Growth Behavior of Short Cracks in SiC- Reinforced LAS Glass-Ceramic Composites Journal of Materials Science Letters Luh, E., Y., Dauskardt, R., H., Ritchie, R., O. 1990; 9: 719-725
  • On The Interpretation of The Fractal Character of Fracture Surfaces Acta Metallurgica et Materialia Dauskardt, R., H., Haubensak, F., Ritchie, R., O. 1990; 2 (38): 143-59
  • Cyclic Fatigue-Crack Propagation Behavior in Pyrolytic Carbon-Coated Graphite for Prosthetic Heart-Valve Applications Ritchie, R., O., Dauskardt, R., H. edited by Kitagawa, H., Tanaka, T. 1990
  • Cyclic Fatigue-Crack Propagation, Stress-Corrosion and Fracture-Toughness Behavior in Pyrolytic Carbon-Coated Graphite For Prosthetic Heart Valve Applications Journal of Biomedical Materials Research Ritchie, R., O., Dauskardt, R., H., Yu, W., Brendzel, A., M. 1990; 2 (24): 189-206
  • Transient Subcritical Crack-Growth Behavior in Transformation-Toughened Ceramics Acta Metallurgicaet Materialia Dauskardt, R., H., Carter, C., Veirs, D., K., Ritchie, R., O. 1990; 11 (38): 2327-336
  • Cyclic Fatigue-Crack Propagation in Mg-PSZ Ceramics Journal of the American Ceramics Society Dauskardt, R., H., Marshal, D., B., Ritchie, R., O. 1990; 4 (73): 893-903
  • Crack Tip Transformation Zones in Toughened Zirconia Journal of the American Ceramics Society Marshall, D., B., Shaw, M., C., Dauskardt, R., H., Ritchie, R., O., Readey, M., Heuer, A., H. 1990; 9 (73): 2659-666
  • Cyclic Fatigue-Crack Propagation in Ceramics: Long and Small Crack Behavior Steffen, A., A., Dauskardt, R., H., Ritchie, R., O. edited by Kitagawa, H., Tanaka, T. 1990
  • SPATIALLY RESOLVED RAMAN-SPECTROSCOPY STUDY OF TRANSFORMED ZONES IN MAGNESIA-PARTIALLY-STABILIZED ZIRCONIA JOURNAL OF THE AMERICAN CERAMIC SOCIETY Dauskardt, R. H., Veirs, D. K., Ritchie, R. O. 1989; 72 (7): 1124-1130
  • FRACTURE-TOUGHNESS, FATIGUE CRACK-PROPAGATION AND CREEP-RUPTURE BEHAVIOR IN THICK SECTION WELDMENTS OF 3CR-MO PRESSURE-VESSEL STEELS DEVELOPED FOR HIGH-TEMPERATURE HIGH-PRESSURE HYDROGEN SERVICE HIGH TEMPERATURE TECHNOLOGY SPENCER, P. N., Dauskardt, R. H., Parker, E. R., Ritchie, R. O. 1989; 7 (1): 17-26
  • Application of Spatially Resolved Raman Spectroscopy in the Study of Transformation Zones in PSZ Journal of the American Ceramics Society Dauskardt, R., H., Veirs, D., K., Ritchie, R., O. 1989; 7 (72): 1124-30
  • Effects of In Situ Phase Transformation on Fatigue-Crack Propagation in Titanium-Nickel Shape-Memory Alloys Dauskardt, R., H., Duerig, T., W., Ritchie, R., O. edited by Otsuka, K., Shimiza, K. 1989
  • Cyclic Fatigue-Crack Growth Behavior in Ceramics Closed Loop Dauskardt, R., H., Ritchie, R., O. 1989; 2 (17): 7-17
  • Fracture-Toughness, Fatigue-Crack Propagation and Creep-Rupture Behavior in Thick-Section Weldments of 3Cr-Mo Pressure-Vessel Steels Developed for High-Temperature/High-Pressure Hydrogen Service High Temperature Technology Spencer, P., N., Dauskardt, R., H., Parker, E., R., Ritchie, R., O. 1988; 2 (8): 17-26
  • Two-Dimensional Spatially Resolved Raman Spectroscopy of Solid Materials Veirs, D., K., Rosenblatt, G., M., Dauskardt, R., H., Ritchie, R., O. edited by Newburg, D., E. 1988
  • EFFECTS OF PREEXISTING GRAIN-BOUNDARY MICROVOID DISTRIBUTIONS ON FRACTURE-TOUGHNESS AND FATIGUE CRACK-GROWTH IN LOW-ALLOY STEEL ACTA METALLURGICA Dauskardt, R. H., Pendse, R. D., Ritchie, R. O. 1987; 35 (9): 2227-2242
  • Effects of Pre-Existing Grain Boundary Microvoid Distributions on Crack Growth under Monotonic and Cyclic Loading Acta Metallurgicaet Materialia Dauskardt, R., H., Pendse, R., D., Ritchie, R., O. 1987; 9 (35): 2227-42
  • Fatigue Crack Propagation in Transformation-Toughened Zirconia Ceramic Journal of the American Ceramics Society Dauskardt, R., H., Yu, W., Ritchie, R., O. 1987; 10 (70): C-248 - C-252
  • Fatigue Crack Propagation Behavior in Pressure Vessel Steels for High Pressure Hydrogen Service Dauskardt, R., H., Ritchie, R., O. edited by Nisbett, E., G. 1986
  • Laboratory-Scale Semi-Continuous Casting of Aluminum Alloys Metals and Materials Damm, O. F. R., A., Dauskardt, R., H., Garrett, G., G. 1986; 9 (2): 565-6