Figure 2

Electrocapillary actuation of liquid metal. (a) Liquid metal resting in a quasi-planar reservoir exerts no lateral pressure. (b) A positive DC voltage creates a potential gradient on the liquid-metal surface near the primary channel entrance, resulting in a corresponding surface-tension gradient and generating Marangoni forces. The liquid metal now exerts a positive pressure on the channel entrance that is opposed by the channel’s capillary pressure. (c) Above the critical voltage threshold, the pressure exerted by the liquid metal exceeds the capillary pressure, and the liquid metal enters the channel. Flow is facilitated by the pressure-relief channel at the opposite end of the reservoir, which prevents a negative pressure build-up at the trailing edge of the liquid metal.