Liquid micromotor driven by continuous electrowetting

This paper aims to acclaim surface tension as a practical microactuation force for MEMS, by developing the ground micromachining technologies and demonstrating a few prototypes including a liquid micromotor. A mechanism called continuous electrowetting is used to drive liquid-metal droplets along microchannels by controlling surface tension with electric potential. The paper first identifies and addresses key issues in employing this powerful surface-tension drive for MEMS throughout the design, fabrication, and testing of a simple test device. The development eventually leads us to a device called liquid micromotor, which demonstrates continuous travel of a mercury drop along a loop of microchannel. Wear-free and smooth rotation is achieved with a speed of 9.4 cm/s at a driving voltage of 10 V.