A micromechanical model for the swelling effect on visco-super-elastic and damage self-healing behaviors of hydrogels reinforced by nanoparticles

In the present article, a micromechanical model is developed for the visco-super-elastic behavior of swollen hydrogel-based nanocomposites. The model formulated in a finite strain context introduces explicitly the hydrogel network features in terms of swelling and dynamic breaking-recombination. The effective interactions between the nanoparticles and the swollen hydrogel network are considered using a micro-macro scale transition within the Eshelby inclusion theory. The model is compared to experimental observations of a high-swelling capacity hydrogel-based nanocomposite reinforced with different concentrations of nanoparticles. The model is firstly identified using experimental data at an initial swelling state in terms of stress-strain response, energy dissipation and ultimate properties. The predictive capability of the model is then verified on a wide range of swelling ratios for a given nanofiller concentration. The efficiency of the model is further critically discussed by comparisons with history-dependent data under stretching-retraction and self-healing. The effects of nanoparticles and swelling on the self-healing behavior are shown thanks to the model.