Modelling of chemo-mechanical coupling in polymer gels via nonlinear finite element method

Design of multifunctional biomimetic materials that exhibit large amplitude actuation through chemical triggers has been a challenge in the field of smart materials. Polymer gels that utilize self-oscillating Belousov Zhabotinsky (BZ) reactions are pioneers among smart materials due to their biomimetic characteristic of chemo-mechanical transductions. Here, we present a computational framework to simulate the dynamics of self-oscillating polymer gels that undergo large deformations under isothermal conditions. Unlike earlier approaches, we harness a complete nonlinear finite element framework that combines the reaction-diffusion phenomena occurring in BZ reaction, with elastic deformations of the polymer gel. Specifically, we use three variable Oregonator model to incorporate reaction kinetics, non-Gaussian mechanical theory for elastic deformations and Flory-Huggins theory to couple the chemical kinetics with the deformation. We demonstrate that actuation capacity of self-oscillating polymer gels can be amplified and controlled by manipulating the reaction kinetics under specific conditions. We believe that our approach brings in a new perspective to design complex bio-inspired systems and provides the necessary framework to control their behaviour.