Elastomer membrane actuators utilizing ultra-thin metal electrodes

We prepare a thin (similar to 100 mu m) silicone-based elastomer membrane and sputter ultra-thin copper electrodes (16192 nm) onto each side of the film. Voltages of varying magnitude (1-8 kV) are applied to the electrodes causing an electrostatic pressure to develop which then compresses the elastomer in the through thickness direction. The edges of the membrane are constrained against in-plane expansion, forcing the membrane to deform out of plane. The in-plane strains developed by applying an electric field are characterized by measuring the stiffness of the membrane via indentation at different applied voltages. Closed-form solutions for membrane deflection are used with the experimental measurements to determine the relationship between the modulus of the cracked electrode/elastomer multi-layer and the electrically induced in-plane strain. Analytical models predicting the relationship between electrode crack spacing, layer properties, and effective modulus of the multi-layer are presented. Building on the knowledge gained from the membrane experiments, uni-axial tension specimens of an electrode/elastomer multi-layer are tested and preliminary results discussed.