Dielectric Elastomers: An Investigation in the Thermal Effects on Compliant Electrode Composition

Dielectric Elastomers (DE) are soft polymers sandwiched between two electrodes that have the unique ability to exhibit large strains when exposed to an external electric potential. This property makes these polymers popular candidates for applications in soft robotic, actuators, and energy harvesting. However, it is the applied electrodes that govern this phenomenon, for this reason it is important for research to be done on the characterization of these electrodes’ properties. Environmental parameters such as varying temperature have the potential to alter material characteristics which can cause disruption of the device intended performance. The goal of this research is to investigate thermal effects on the electromechanical properties of DE’s electrodes. Four carbon grease electrode samples were created using a mixture of high vacuum grease (Dow Corning, USA), Ketjen black carbon powder, and carbon graphite (Asbury Carbons, USA). The electrical percolation threshold was met at a ratio of 0.5:7g and 1:7 g of Ketjen black carbon black samples, while the threshold was met at a ratio of 5:7 g and 6:7g of graphite samples. Three sets of experiments were conducted to investigate the thermal effects the carbons samples produce in voltage induced actuation, max breakdown voltage, and elongation breakpoint tests where the four samples are subjected to various temperatures. From these experiments, a comparative analysis on parameters like young’s modulus, induced actuation displacement, breakdown voltage, and applicable force are tabulated and presented.