Abstract

Electrodes currently used in dielectric elastomer actuators (DEAs) present several issues arising from the mechanical mismatch with the dielectric elastomer, processing complexities, poor adherence, and low structural stability, beside single-use characteristics. To overcome these limitations, a commercial polydimethylsiloxane (PDMS) elastomer was mixed with a liquid conductive carbon grease (CG) for developing a high flexible elastomeric electrode with reusable characteristics and good adherence. The PDMS-CG composites presented an electrical percolation threshold at concentrations of 10 wt% and maximum conductivities around 10−3 S/m, and lower elastic modulus than pure PDMS, making them suitable as electrode for DEAs. The conductive PDMS/CG composites further presented structural stability and reversible adhesion to several surface, including to pure PDMS surface. This novel PDMS composite can be used as a reusable compliant electrode for high performance DEA using pure PDMS as a dielectric. Three pre-stretching configurations were analyzed to validate the DEA behavior using the elastomeric electrode: uniaxial, linear biaxial, and equi-biaxial. Noteworthy, the resulting actuations from the compliant PDMS-CG reusable electrodes were as similar as the actuations using fully compliant pure CG electrodes. A model to understand the effect of the compliant-solid electrode on the DEA actuator was further developed. Our all-PDMS DEA was further validated for tensile artificial muscle applications actuating a dead-load and an 3D-printed arm.