Frequency-independent breakdown strength of dielectric elastomers under AC stress

Abstract

Soft insulators are the main component used in dielectric elastomer actuators (DEAs). It follows that dielectric properties like permittivity and dielectric strength of the insulator can strongly influence the maximum dynamic actuation performance of DEA devices. We observed an increasing breakdown voltage with increasing driving AC voltage frequency for silicone-based dielectric films. Despite the breakdown voltage increase, we demonstrate that there is no actual breakdown electric field rise with varying frequencies. We show that the voltage behavior is rather compatible with a constant dielectric breakdown field model and the slow mechanical response of the elastomer.