Dielectric elastomeric bimorphs using electrolessly deposited silver electrodes

Metallic thin films, which are widely used for micro-electronics circuits, are seldom used as the electrodes for dielectric elastomer actuators (DEA). This is because metalized film restrains the lateral strain of soft dielectric elastomer. In this paper, we demonstrated utilizing metalized elastomeric layers to make a bimorph capable of a large bending. A compliant silver electrode is deposited on onto a VHB tape (F-9469 PC) using electroless deposition method, as for mirror silvering. The deposited silver is 200 nm thick and highly conductively though having an uneven surface. A silvered DEA bimorph is made of an active layer of silvered VHB elastomers and a passive layer of polydimethylsiloxane (PDMS). Experiments show that the silvered dielectric elastomer actuator is capable of producing a large bending, with a curvature of 32 mm for a 20 mm length at a driving voltage of 3000V. In addition, the electrolessly silvered elastomeric capacitor (130 μm thick VHB as dielectric) exhibits a breakdown voltage of 4kV, higher than 2kV of the silver-greased capacitor. In addition, the silvered VHB layer is found to be able to self clear after electrical breakdown. It remains functional at a lower voltage after surviving an electrical breakdown.