Modeling and Characterization of Viscoporoelastic Behavior and Rate-Dependent Adhesion in Gels
Author(s)
He, Dongjing
Advisor(s)
Editor(s)
Collections
Supplementary to:
Permanent Link
Abstract
This thesis investigates the theoretical modeling and experimental characterization of gels, focusing on visco-poroelasticity and rate-dependent adhesion. Gels, composed of cross-linked polymer networks infused with solvent molecules, exhibit time-dependent behavior due to polymer chain rearrangement and solvent migration, leading to macroscopic viscoelasticity and poroelasticity. A comprehensive nonlinear thermodynamics framework is proposed to connect various rheological models with solvent transport responses in gels. This framework introduces a novel element, the osmotic container, to analyze the coupling of solvent migration with different components of the rheological models. To characterize visco-poroelastic gels, the dynamic indentation boundary value problem is solved analytically, leading to a theoretical solution for phase lag calculation. Based on the solution, an experimental approach using atomic force microscope is applied to determine the material parameters of polyacrylamide-alginate hydrogels, validating the methodology. Additionally, this thesis examines rate-dependent adhesion during indentation tests on polyacrylamide hydrogels, revealing a down-and-up transition in pull-off force related to pull-off velocity. This behavior is modeled through a rate-dependent contact adhesion problem that incorporates bonding-debonding kinetics. Overall, this work enhances the understanding of both bulk and interfacial time-dependent behaviors in gels and proposes robust methodologies for characterizing their mechanical properties.
Sponsor
Date
2025-05-16
Extent
Resource Type
Text
Resource Subtype
Dissertation