Actuated elastomers with rigid vertical electrodes

This paper presents a novel design of actuated elastomers using rigid, vertical standing electrodes. The electrodes of high rigidity are designed to have small width, small gaps and large depth in order to produce large electrostatic forces at a moderate voltage, as well as to reduce the constraining effect on the soft elastomers. This novel design embodies lateral stacking to accumulate small strain into an adequate displacement for micro-actuation. Analytical and numerical analyses are performed to evaluate the force-displacement characteristics of the elastomer actuators. It is shown that actuation of the novel design is not limited by the electrostatic pull-in instability, and it is capable of travelling a large range at a high electric field. In addition, feasibility of fabrication processes is studied. It is shown that lateral stacking can readily be realized by filling liquid elastomers into deep, narrow and vertical trenches. A theoretical benchmark comparison with a conventional air-gap electrostatic comb drive indicates that the new elastomer actuator promises great flexibility, large attraction force and robustness against shock and dust blockage.