Many dielectric polymer materials show a specific deformation by applying an electric field. Plasticized polyvinyl chloride (PVC) gel, transparent soft material, can be use as a focus-controllable lens because its electrical actuation is speedy and reversible. Electrostatic actuator using polyethylene terephthalate (PET) film shows a high-speed oscillation by applying an electric field, and therefore the electrostatic actuator can be use for a polymer speaker or oscillator.