Effects of two scaling exponents on biaxial deformation and mass transport of swollen elastomers

Abstract

In this study, we investigate the effects of two scaling exponents on the biaxial deformation and mass transport of swollen elastomers. Two scaling exponents are included in an extended version of the Flory–Rehner model (Okumura et al., J. Mech. Phys. Solids, 2016); two scaling exponents are used to adjust the swelling effects on the Young's modulus and osmotic pressure of swollen elastomers, resulting in the ability to predict swelling-induced strain softening under uniaxial tensile loading. It is found that when biaxial tensile loading is given under stress control, strain softening is accelerated by increasing the biaxial stress ratio, while under strain control, the responses become more complicated, which can be interpreted by considering that Poisson's ratio at equilibrium free swelling can take negative values depending on the two scaling exponents. Further, the effect of the two scaling exponents on mass transport is discussed by analyzing the swelling kinetics of a gel layer constrained on a rigid substrate.