Plasticized polyvinyl chloride (PVC) gels are a promising material for soft robotic actuators due to their fast response rates and remarkable deformation characteristics. A variety of different actuator types can be made with PVC gels because their deformation via anodophilic creep is highly customizable by alteration of the electrode configuration, applied electric field, surface microstructure, and plasticizer content. This level of customization is not typically possible with other electroactive polymer actuators. Several attempts have been made to model PVC gel anodophilic creep actuation. Most of these have been limited in scope to particular actuator types and are phenomenological models. An accurate predictive model is necessary for the implementation and control of these actuators in the field of soft robotics, and this can be better achieved through the use of a physics-based electromechanical model.
In this paper the underlying mechanisms for PVC gel actuation are discussed, and simulation results are shown. We present our finite element model which seeks to move towards a more general model for PVC gels derived from first principles. This electromechanical model is based on the Maxwell stress that is developed within the PVC gel along the anode when an electric field is applied. COMSOL Multiphysics modeling software is utilized for the simulation of PVC gel deformation when exposed to an electric potential. In addition, an experimental study of PVC gels was conducted to verify the model for mesh-type contraction actuators, and the simulated results provide context and support for the underlying mechanisms discussed.