Samya Sen, Ph.D.
Postdoctoral Scholar, Materials Science and Engineering
Bio
Dr. Samya Sen is a Postdoc in the Appel Lab at Materials Science and Engineering. He earned his doctorate in mechanical engineering from University of Illinois Urbana-Champaign with Prof. Randy H. Ewoldt. His main research interests are soft materials, rheology, and non-Newtonian fluid mechanics. His current focus is studying the rheology of and developing novel hydrogels for biomedical applications.
Current Research and Scholarly Interests
Samya's research interests are primarily soft materials and complex fluids. He uses experimental techniques of fundamental rheology in conjunction with non-Newtonian fluid mechanics to model, characterize, design, and understand soft material behavior. The applications of his research range from yield-stress fluid design in consumer products, industrial materials, and wildfire suppression. His current research projects as a postdoctoral researcher with Prof. Appel is in the rheological of novel hydrogels for biomedical applications, including improved drug delivery. His focus is on developing transient, stimuli-responsive materials with tunable mechanical and mass transport properties which can be tuned in situ and in vitro for controlled drug-release profiles. He also works on mathematical modeling of mass transport, structural evolution, and constitutive behavior of polymeric and colloidal materials in the context of soft biomaterials.
All Publications
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Biomimetic Non-ergodic Aging by Dynamic-to-covalent Transitions in Physical Hydrogels.
ACS applied materials & interfaces
2024
Abstract
Hydrogels are soft materials engineered to suit a multitude of applications that exploit their tunable mechanochemical properties. Dynamic hydrogels employing noncovalent, physically cross-linked networks dominated by either enthalpic or entropic interactions enable unique rheological and stimuli-responsive characteristics. In contrast to enthalpy-driven interactions that soften with increasing temperature, entropic interactions result in largely temperature-independent mechanical properties. By engineering interfacial polymer-particle interactions, we can induce a dynamic-to-covalent transition in entropic hydrogels that leads to biomimetic non-ergodic aging in the microstructure without altering the network mesh size. This transition is tuned by varying temperature and formulation conditions such as pH, which allows for multivalent tunability in properties. These hydrogels can thus be designed to exhibit either temperature-independent metastable dynamic cross-linking or time-dependent stiffening based on formulation and storage conditions, all while maintaining structural features critical for controlling mass transport, akin to many biological tissues. Such robust materials with versatile and adaptable properties can be utilized in applications such as wildfire suppression, surgical adhesives, and depot-forming injectable drug delivery systems.
View details for DOI 10.1021/acsami.4c03303
View details for PubMedID 38862125
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Soft glassy materials with tunable extensibility.
Soft matter
2023
Abstract
Extensibility is beyond the paradigm of classical soft glassy materials, and more broadly, yield-stress fluids. Recently, model yield-stress fluids with significant extensibility have been designed by adding polymeric phases to classically viscoplastic dispersions [Nelson et al., J. Rheol., 2018, 62, 357; Nelson et al., Curr. Opin. Solid State Mater. Sci., 2019, 23, 100758; Dekker et al., J. Non-Newtonian Fluid Mech., 2022, 310, 104938]. However, fundamental questions remain about the design of and coupling between the shear and extensional rheology of such systems. In this work, we propose a model material, a mixture of soft glassy microgels and solutions of high molecular weight linear polymers. We establish systematic criteria for the design and thorough rheological characterization of such systems, in both shear and extension. Using our material, we show that it is possible to dramatically change the behavior in extension with minimal change in the shear yield stress and elastic modulus, thus enabling applications that exploit orthogonal modulation of shear and extensional material properties.
View details for DOI 10.1039/d3sm01150j
View details for PubMedID 38078477
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Thixotropic spectra and Ashby-style charts for thixotropy
JOURNAL OF RHEOLOGY
2022; 66 (5): 1041-1053
View details for DOI 10.1122/8.0000446
View details for Web of Science ID 000848363100002
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Thixotropy in viscoplastic drop impact on thin films
PHYSICAL REVIEW FLUIDS
2021; 6 (4)
View details for DOI 10.1103/PhysRevFluids.6.043301
View details for Web of Science ID 000652861500001
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Rheology of fibre suspension flows in the pipeline hydro-transport of biomass feedstock
BIOSYSTEMS ENGINEERING
2020; 200: 284-297
View details for DOI 10.1016/j.biosystemseng.2020.10.009
View details for Web of Science ID 000598489200007
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Viscoplastic drop impact on thin films
JOURNAL OF FLUID MECHANICS
2020; 891
View details for DOI 10.1017/jfm.2020.147
View details for Web of Science ID 000524939800001
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Base-triggered self-amplifying degradable polyurethanes with the ability to translate local stimulation to continuous long-range degradation
CHEMICAL SCIENCE
2020; 11 (12): 3326-3331
Abstract
A new type of base-triggered self-amplifying degradable polyurethane is reported that degrades under mild conditions, with the release of increasing amounts of amine product leading to self-amplified degradation. The polymer incorporates a base-sensitive Fmoc-derivative into every repeating unit to enable highly sensitive amine amplified degradation. A sigmoidal degradation curve for the linear polymer was observed consistent with a self-amplifying degradation mechanism. An analogous cross-linked polyurethane gel was prepared and also found to undergo amplified breakdown. In this case, a trace amount of localized base initiates the degradation, which in turn propagates through the material in an amplified manner. The results demonstrate the potential utility of these new generation polyurethanes in enhanced disposability and as stimuli responsive materials.
View details for DOI 10.1039/c9sc06582b
View details for Web of Science ID 000528663000021
View details for PubMedID 34122840
View details for PubMedCentralID PMC8152679
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Acid-Triggered, Acid-Generating, and Self-Amplifying Degradable Polymers
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
2019; 141 (7): 2838-2842
Abstract
We describe the 3-iodopropyl acetal moiety as a simple cleavable unit that undergoes acid catalyzed hydrolysis to liberate HI (p Ka ∼ -10) and acrolein stoichiometrically. Integrating this unit into linear and network polymers gives a class of macromolecules that undergo a new mechanism of degradation with an acid amplified, sigmoidal rate. This trigger-responsive self-amplified degradable polymer undergoes accelerated rate of degradation and agent release.
View details for DOI 10.1021/jacs.8b07705
View details for Web of Science ID 000459642000009
View details for PubMedID 30698426