Differential Electrode Design for Electrostatic Actuator in Conducting Media

We present the design, modeling and experimental validation of a novel differential actuation scheme to enhance the performance of comb-drive electrostatic actuators in aqueous media. The new design mitigates the losses in parasitic impedance and extends the actuation of the devices into frequency ranges suitable for biological samples, achieving a displacement of 3.5 mum in 100 mM KCl. The frequency dependence of the electrostatic force has been tested by operating the devices in media of different ionic concentrations. Circuit models for the electric double layer phenomena are used to analyze the device behavior.