Mechanics of Composite Hydrogels

Abstract

Composite hydrogels – which consist of fillers in a swollen polymeric matrix – are ubiquitous structural components of biological materials, biomedical devices, food, and consumer products. The mechanical properties of composite hydrogels are pivotal for their respective applications, and are governed by physical processes which remain unexplored. This thesis explores the physical processes that underlie (i) structure formation in composite hydrogels, viewed from the perspective of the self-assembly of patchy particles; (ii) linear viscoelastic stress relaxation in composite hydrogels, as a manifestation of athermal relaxation dynamics; (iii) nonlinear compression stiffening in composite hydrogels, arising from complex particle dynamics that arise during compression; and (iv) design methods for composite hydrogels, as functional materials with programmable morphologies and stimuli-responsivity. These results provide a framework for understanding the mechanics of composite hydrogels in nature and technology.