Pulsed actuation avoids failure in dielectric elastomer artificial muscles

Abstract

Dielectric elastomer actuators (DEAs) are a class of artificial muscles capable of large linear strains (well over 100%), and with high energy density, and low cost and weight. One of the most prominent failure modes of a DEA is electrical breakdown, which can damage the device permanently, limiting its deformation capability. Breakdown is also common, since to maximize energy output, devices often operate near the breakdown limit. Elucidating breakdown mechanisms, as well as finding ways to prevent it, are of intense research interest. We show that by applying short electrical pulses, one could minimize the exposure of the DEAs to high leakage current, which is one of the main mechanisms for electrical breakdown. This allows one to operate at significantly higher potentials than the DC breakdown voltage. By applying pulses, we demonstrate up to 81.7% area strain repeatedly, at voltages more than twice the DC breakdown limit, without the risk of failure. The pulsed operation mode of DEAs accommodating higher voltages than possible with DC represents an opportunity for potential applications, safer and simpler device designs, and a technique for further study of DEA breakdown mechanisms.