Current leakage performance of dielectric elastomers under different boundary conditions

In the past decade, dielectric elastomers have become promising candidates in the applications of soft electromechanical transducers due to their outstanding properties of large deformation and high energy density. Current leakage of dielectric elastomer is one of the important dissipative mechanisms affecting the energy conversion efficiency. In this work, we experimentally investigate the current leakage performance of dielectric elastomers with different boundary conditions. We find that for displacement-type boundary conditions, the transition from Ohmic conduction to non-Ohmic conduction is abrupt near the critical electric field. By comparison, for force-type boundary conditions, the current leakage density versus electric field curve is smooth and is fit well by an exponential function. The equivalent resistivity of dielectric elastomers under force-type boundary conditions is approximately an order of magnitude smaller than that under displacement-type boundary conditions. The difference is qualitatively explained by a microscopic physical model. These results will help to design and optimize dielectric elastomer transducers to improve their energy conversion efficiency.