Poro-visco-hyperelastic modelling of hydrogel composites

Abstract

Hydrogel composites are cross-linked polymeric networks filled with particles and high water content. They are widely used as tissue/cell culture scaffolds, biomedical adhesives and healthcare products because of their biocompatibility and tuneable properties. As the performance of hydrogel composites significantly relies on their mechanical properties, it is required to understand and to model their mechanical behaviours. Hydrogel composites are believed to have hyperelasticity, viscoelasticity and poroelasticity. Obviously, it s difficult to capture all the three within one mechanical model. In recent years, researchers proposed hybrid models for visco-hyperelasticity for biological tissues [Lucas et al., 2008] and poroviscoelasticity for hydrogel [Wang et al., 2014]. As an attempt to provide a unified model for hydrogel composites, a poro-visco-hyperelastic model was proposed in this study. This porovisco-hyperelastic model was based on Quasi-Linear Viscoelastic (QLV) model proposed by Fung [Fung, 1981]. Considering the similarity of the phenomena of poroelasticity and viscoelasticity, a 3-term Prony series was adopted as the reduction part in QLV to model the viscoelasticity and the poroelasticity of hydrogel composites. Mooney-Rivlin model was selected as the hyperelastic part in QLV. To evaluate this model, 6 types of Poly(ethylene glycol) diacrylate (PEGDA)-Silica hydrogel composites with different concentrations of polymer matrix and silica nanoparticles were fabricated and tested under uniaxial compressive load with 4 different strai