Figure 5

Electrochemical actuation of liquid metal. In ambient conditions the liquid metal has a uniform negative surface charge and attracts counter-ions in the alkaline electrolyte. (a) This charge distribution is disturbed when an external bias creates a potential gradient in the vicinity of the liquid metal. (b) An oxidative reaction is created, especially near the channel opening where the oxidative potential is greatest, and (c) the liquid metal begins slowly flowing into the channel. (d) At higher potentials the advance is halted at some critical length l _c , where the liquid metal cannot break through the rapidly forming oxide layer at the leading edge.