NUMERICAL AND EXPERIMENTAL STUDY OF EQUILIBRIUM SWELLING OF STIMULI RESPONSIVE COMPOSITE HYDROGELS

Abstract

This study addresses fluid diffusion and large deformation of polymer network of composite hydrogels subjected to swelling. First, the equilibrium swelling of core/shell composite hydrogels is modeled by applying a constitutive model derived based on the free energy imbalance relation, and extending it to capture the mutual interaction between core and shell domains. Temperature sensitivity and coupled pH/temperature sensitivity are incorporated in the model. A two-step swelling behavior observed in core/shell gels with thick shells, can be predicted with the developed model. Second, another composite hydrogel made by co-polymerization of agarose and carbopol is studied when it is subjected to swelling at pH values ranging from highly acidic to highly basic. The influence of agarose and carbopol on the stiffness and swelling ratio of these gels are investigated. These findings might be used as a guide to tailor agarose-carbopol composite hydrogels to achieve desirable mechanical strength and swelling properties.