An actuator includes a substrate including an insulating surface, a first electrode positioned on the insulating surface, and a flexible drive plate which opposes the insulating surface. Te actuator also includes a conductive liquid positioned between the insulating surface and the flexible drive plate, and the conductive liquid directly or indirectly contacts the insulating surface and the flexible drive surface. Moreover, the actuator includes a potential application device electrically coupled to the first electrode and configured to apply a potential to the first electrode.