Modeling of multiphase smart hydrogels responding to pH and electric voltage coupled stimuli

Abstract

A model, entitled the multi-effect-coupling pH -electric-stimuli (MECpHe) model, is presented and analyzed for the response of smart hydrogels to changes in the coupled stimuli of an external electric field and the solution pH. It considers finite deformations, the electric potential and distribution of fixed charge density in the hydrogel and surrounding solvent. The MECpHe model is validated with previously published experimental measurements and good agreement is shown. A steady-state study is carried out for various pH values and applied electric voltages to ascertain the impact of these on the deformation of the hydrogel and distribution of ionic species, electric potential, and fixed charge density, both inside the hydrogel as well as in the surrounding solvent. © 2007 American Institute of Physics.