Characterization of electrostatic gap-closing actuator arrays in aqueous conditions

We demonstrate high-force-density rapid actuation of electrostatic gap-closing actuator (GCA) arrays operating in an aqueous environment. These devices are designed to generate up to 4.6 mN at 6 V drive signal amplitudes and have measured pull-in times as fast as 121 μs with no electrolysis. We present a new model for the dynamics of aqueous GCA operation which includes the inertia of the squeezed fluid and proximity of the substrate to the device layer. The actuators operate in deionized water, and preliminary tests demonstrate actuation in ionic solutions (10 mM) and partial operation of submerged inchworm motors based on GCA arrays.