Date of Award

8-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Materials Science and Engineering

Committee Chair/Advisor

Dr. Olga Kuksenok

Committee Member

Dr. Igor Luzinov

Committee Member

Dr. Ulf D. Schiller

Committee Member

Dr. Marek W. Urban

Abstract

Topography and morphology have considerable impacts on the functionalities of soft materials in an entire range of applications from smart optics to tissue engineering. Adapting theoretical and computational approaches, we focus on the dynamics of pattern formation and morphology development in polymer networks. This dissertation starts with studying the dynamical control of pattern formation in confined thermo-responsive poly(N-isopropylacrylamide) (PNIPAAm) gel films. The patterns are formed due to mechanical instabilities. We perform a linear stability analysis and identify the limits of this analysis in predicting pattern formation in gels. We then study the restructuring between patterns and hysteresis phenomena under stretching-compression cycles. We show that the characteristics of the patterns could be regulated dynamically by changing the rates of stretching and compression of the sample along its width. We also propose a model that captures the photo-responsiveness of PNIPAAm-based gels with host-guest interactions between pendant azobenzene (Azo) moieties and aqueous a-cyclodextrin (a-CD). Based on the proposed model, we run simulations and demonstrate that the swelling-induced pattern formation is dynamically accessible in the constrained and free gels by the variations in the illumination conditions. Finally, we study the morphology development in crosslinked binary and ternary polymer blends containing poly(hydromethylsiloxane) (PHMS). We propose an approach to model the hydrosilylation reaction on the mesoscale. We then perform simulations and show that the crosslinking reactions arrest the phase separation of blends and limit the characteristic length scale of the system that is substantially affected by the properties of the sacrificial components.

Author ORCID Identifier

0000-0001-9350-6112

Available for download on Thursday, August 31, 2023

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