The multiplicative decomposition of the deformation gradient in the multiphysics modeling of ionic polymers

A thermodynamically consistent modeling of the non-linear multiphysics behavior of ionic polymers is presented and discussed. A key ingredient of the model is the treatment of the electrically induced deformations, resulting in a large bending motion when ionic polymers are employed in IPMCs (Ionic Polymer-Metal Composites). With specific reference to the mechanics, the position of the linear models for ionic polymers is discussed and set within a formalized linearization procedure. A set of numerical experiments is developed, showing the capability of the model to capture the fundamental features of the actuation mechanism.