Constitutive modelling of responsive and non-responsive polymer gels with limited compressibility

Design of futuristic synthetic materials to replicate biological mechanisms has been a challenge for science and engineering. Polymer gels that are intrinsically powered by self-oscillating Belousov Zhabotinsky (BZ) reaction are systems that utilize chemo-mechanical transduction to produce mechanical work from chemical energy. Here, we develop the chemo-mechanical theory for modelling these systems under isothermal conditions. Our approach harnesses the finite element framework to combine the reaction-diffusion phenomena with large elastic deformations of the non-gaussian compressible polymeric networks. In particular, we use Oregonator model to capture BZ kinetics while the modified Flory-Huggins theory is used to capture interactions between BZ-catalyst and polymer gel. Using our model we simulated the dynamics of BZ and non-responsive gels under equilibrium and transient conditions; we validated our results with the existing models and experimental results. In essence, we develop and establish a framework to design and study responsive materials with complex geometries. Moreover, we believe that by extending our methodology it is possible to capture large deformations akin to volume phase transitions in polymer gels under non-isothermal conditions.