By variation of liquid Wood metal's environment in NaOH solution and application of electric field with graphite electrode

surface tension of the liquid metal

interfacial electrochemical reaction

generation of oxidation film

and other dynamic processes were studied. The results showed that thin oxidation film on the surface of Wood alloy droplets which was formed by anodic oxidation reaction quickly reduced surface tension of Wood alloy and the oxidation film on surface of liquid alloy droplets would return to neutral state by cathodic reduction reaction within 3 seconds. The electrical capillary force broke the oxide film so that metal oxides reacted with NaOH to generate ions of Sn(OH)62-、SnO32-、SnO22-、PbO32-、Cd(OH)42- which altered solution colors with a white precipitate of Bi2O3-Bi(OH)3 copolymer. The dielectric wetting and solution electrowetting on thin film essentially had the same mechanism. With the increase of voltage

the surface tension was decreased and electrowetting spreading process was occurred obviously

but the wetting angle exhibited saturation as a result of limited number of OH- ions adsorbed on alloy droplets by electrochemical reactions.