Characterization of the dielectric breakdown field strength of PDMS thin films: thickness dependence and electrode shape

During the operation of a dielectric elastomer generator (DEG) the energy harvested should be maximized. A higher electrical field strength in the DEG leads to a higher energy gain. However, the applied electrical field strength is restricted due to the dielectric breakdown field strength of the dielectric elastomer in the generator. For appropriate operation of the generator the dielectric breakdown field strength of the elastomer has to be known. From literature it is known that the breakdown strength of polymers depends on several parameters like the thickness of the material and the electrode shape. In this work, the dielectric breakdown strength of a novel PDMS thin film material for the fabrication of dielectric elastomer transducers developed by Wacker Chemie AG is investigated. Several PDMS film thicknesses are compared to determine the influence of the film thickness on the breakdown strength. The results show that the expected inverse thickness dependence of the breakdown strength is not valid for the new film material. In fact, no significant thickness dependence of the dielectric breakdown field strength is existent. The electrical characteristics of the measurement setup used for characterization of the dielectric breakdown field strength of the PDMS thin films are investigated using numerical simulations to determine the influence of the electrode shape.