Stanford Advisors

All Publications

  • Impact of Molecular Design on Degradation Lifetimes of Degradable Imine-Based Semiconducting Polymers. Journal of the American Chemical Society Chiong, J. A., Zheng, Y., Zhang, S., Ma, G., Wu, Y., Ngaruka, G., Lin, Y., Gu, X., Bao, Z. 2022


    Transient electronics are a rapidly emerging field due to their potential applications in the environment and human health. Recently, a few studies have incorporated acid-labile imine bonds into polymer semiconductors to impart transience; however, understanding of the structure-degradation property relationships of these polymers is limited. In this study, we systematically design and characterize a series of fully degradable diketopyrrolopyrrole-based polymers with engineered sidechains to investigate the impact of several molecular design parameters on the degradation lifetimes of these polymers. By monitoring degradation kinetics via ultraviolet-visible spectroscopy, we reveal that polymer degradation in solution is aggregation-dependent based on the branching point and Mn, with accelerated degradation rates facilitated by decreasing aggregation. Additionally, increasing the hydrophilicity of the polymers promotes water diffusion and therefore acid hydrolysis of the imine bonds along the polymer backbone. The aggregation properties and degradation lifetimes of these polymers rely heavily on solvent, with polymers in chlorobenzene taking six times as long to degrade as in chloroform. We develop a new method for quantifying the degradation of polymers in the thin film and observe that similar factors and considerations (e.g., interchain order, crystallite size, and hydrophilicity) used for designing high-performance semiconductors impact the degradation of imine-based polymer semiconductors. We found that terpolymerization serves as an attractive approach for achieving degradable semiconductors with both good charge transport and tuned degradation properties. This study provides crucial principles for the molecular design of degradable semiconducting polymers, and we anticipate that these findings will expedite progress toward transient electronics with controlled lifetimes.

    View details for DOI 10.1021/jacs.1c12845

    View details for PubMedID 35179880

  • Dynamic Enamine-one Bond Based Vitrimer via Amino-yne Click Reaction ACS MACRO LETTERS Guo, X., Gao, F., Chen, F., Zhong, J., Shen, L., Lin, C., Lin, Y. 2021; 10 (10): 1186-1190
  • A Design Strategy for Intrinsically Stretchable High-Performance Polymer Semiconductors: Incorporating Conjugated Rigid Fused-Rings with Bulky Side Groups. Journal of the American Chemical Society Liu, D., Mun, J., Chen, G., Schuster, N. J., Wang, W., Zheng, Y., Nikzad, S., Lai, J., Wu, Y., Zhong, D., Lin, Y., Lei, Y., Chen, Y., Gam, S., Chung, J. W., Yun, Y., Tok, J. B., Bao, Z. 2021


    Strategies to improve stretchability of polymer semiconductors, such as introducing flexible conjugation-breakers or adding flexible blocks, usually result in degraded electrical properties. In this work, we propose a concept to address this limitation, by introducing conjugated rigid fused-rings with optimized bulky side groups and maintaining a conjugated polymer backbone. Specifically, we investigated two classes of rigid fused-ring systems, namely, benzene-substituted dibenzothiopheno[6,5-b:6',5'-f]thieno[3,2-b]thiophene (Ph-DBTTT) and indacenodithiophene (IDT) systems, and identified molecules displaying optimized electrical and mechanical properties. In the IDT system, the polymer PIDT-3T-OC12-10% showed promising electrical and mechanical properties. In fully stretchable transistors, the polymer PIDT-3T-OC12-10% showed a mobility of 0.27 cm2 V-1 s-1 at 75% strain and maintained its mobility after being subjected to hundreds of stretching-releasing cycles at 25% strain. Our results underscore the intimate correlation between chemical structures, mechanical properties, and charge carrier mobility for polymer semiconductors. Our described molecular design approach will help to expedite the next generation of intrinsically stretchable high-performance polymer semiconductors.

    View details for DOI 10.1021/jacs.1c04984

    View details for PubMedID 34284578

  • Integrating Emerging Polymer Chemistries for the Advancement of Recyclable, Biodegradable, and Biocompatible Electronics. Advanced science (Weinheim, Baden-Wurttemberg, Germany) Chiong, J. A., Tran, H., Lin, Y., Zheng, Y., Bao, Z. 2021: e2101233


    Through advances in molecular design, understanding of processing parameters, and development of non-traditional device fabrication techniques, the field of wearable and implantable skin-inspired devices is rapidly growing interest in the consumer market. Like previous technological advances, economic growth and efficiency is anticipated, as these devices will enable an augmented level of interaction between humans and the environment. However, the parallel growing electronic waste that is yet to be addressed has already left an adverse impact on the environment and human health. Looking forward, it is imperative to develop both human- and environmentally-friendly electronics, which are contingent on emerging recyclable, biodegradable, and biocompatible polymer technologies. This review provides definitions for recyclable, biodegradable, and biocompatible polymers based on reported literature, an overview of the analytical techniques used to characterize mechanical and chemical property changes, and standard policies for real-life applications. Then, various strategies in designing the next-generation of polymers to be recyclable, biodegradable, or biocompatible with enhanced functionalities relative to traditional or commercial polymers are discussed. Finally, electronics that exhibit an element of recyclability, biodegradability, or biocompatibility with new molecular design are highlighted with the anticipation of integrating emerging polymer chemistries into future electronic devices.

    View details for DOI 10.1002/advs.202101233

    View details for PubMedID 34014619