Actuators based on electroactive polymers use the electrostatic pressure to convert electrical energy into strain energy. Depending on the setup, stack- and roll-actuators can be realized. Here the authors introduce a completely new roll-actuator design, in which bi-axially prestretched electroactive material is winded up around a compressed polymer core. The modeling of this actuator yields to an electromechanically coupled dynamic model, which consists of a non-linear mechanical model to describe the hyperelastic properties of the polymer and an electrical model to describe the electrostatic behavior. Based on this model, the authors discuss the influence of some of the actuators design parameters and present a realized prototype of the polymer core roll-actuator.