Factors influencing the mean-time-to-failure of single-layer uniaxially prestretched silicone-based DEAs

We report an experimental investigation on the influence of electric field, electrode surface area, encapsulation layers and elastomer material on the mean-time-to-failure (MTTF) of single-layer uniaxially prestretched silicone-based dielectric elastomer actuators (DEAs) under constant DC actuation. The DEAs consist of a 12 mu m thick uniaxially prestretched Elastosil 2030/20 or Electro 242-1 silicone membrane sandwiched between 4 mu m thick rectangular carbon black-PDMS electrodes. We operate the DEAs under controlled environmental conditions at 20 degrees C - 90% RH and at 85 degrees C - 85% RH. We use an automated characterization setup that monitors the strain of 6 DEAs vs time. DEAs made from Electro 242-1 have a 4x to 6x longer MTTF than DEA made from Elastosil 2030/20. Increasing the electric field from 60 V/mu m (i.e. approximate to 1% actuation strain) to 90 V/mu m (i.e. approximate to 3% actuation strain) decreases the MTTF by factors 15x-20x, revealing a significant strain - DC lifetime tradeoff. We show that encapsulating the DEAs with a thin soft elastomer is an effective method to increase lifetime by factors 6x-13x at constant field, without significantly changing the actuation strain.