In one embodiment an electrostatic actuator includes: a first conductor associated with each chamber; a second conductor having a plurality of flexible first parts supported by a plurality of second parts, each flexible first part forming at least part of a wall of each chamber and each flexible first part located opposite a corresponding one of the first conductors across a gap; and a voltage source operatively connected to each of the first conductors for selectively applying a voltage between each of the first conductors and the second conductor In another embodiment, an electrostatic actuator includes: a plurality of rigid conductors arranged adjacent to one another along a chamber; and a flexible conductor disposed opposite to and spanning the plurality of first conductors across a gap, the flexible conductor forming at least part of one wall of the chamber such that flexing the flexible conductor flexes the wall to change the volume of the chamber.