Coupled chemo-electro-mechanical finite element simulation of hydrogels: II. Electricalstimulation

Abstract

Certain polyelectrolyte gels are distinguished by a large swelling or bending capabilityunder the influence of external physical, chemical or electrical stimuli. In this paper weinvestigate the mechanisms occurring in polyelectrolyte gels due to externally appliedelectric fields. By applying a coupled chemo-electro-mechanical model which is extendedand predestined for electrical stimulation, we describe the concentrations and theelectric potential in both the gel and the solution as well as the locally differentswelling and shrinking in the gel. The local change of geometry is formulated by alocal osmotic pressure difference between the gel and the solution next to the gelphase. In addition to this effect, the change of the local gel domain leads to a localvariation of the concentration of bound groups and thus to a change of the localconcentrations of mobile ions. As the focus of the presented work we demonstrate thesuperiority of the fully coupled chemo-electro-mechanical description compared to thepreviously developed one-way chemo-electric to mechanical coupled model. Finally,by a qualitative comparison with experimental results, the validity of the fullycoupled chemo-electro-mechanical model for electrical stimulation is demonstrated.