Summary Gallium and its eutectic alloys exhibit complex electrohydrodynamic motions governed by interfacial oxidation and electrocapillary effects under electrochemical settings. However, the interplay between alloy composition and the environment, during such electrohydrodynamic activities, remains insufficiently understood. Here, using high-speed imaging, the motion and deformation of gallium, eutectic gallium-zinc, eutectic gallium-tin, and eutectic gallium-indium droplets were systematically examined under electric fields to elucidate how alloy composition influences polarity, deformation, and voltage thresholds. While the gallium-indium system exhibits anode-directed electrowetting, gallium and gallium-zinc droplets display cathode-directed motion due to oxidation-induced rigidity, and gallium-tin system shows voltage-dependent reversal from tin segregation. Introducing different boundaries, including obstacles, porous meshes, and conductive substrates, reveals that oxide presence and localized electric fields govern deformation, fragmentation, and spreading, uncovering distinct droplet behaviors. A proof-of-concept experiment using the gallium-indium system to transport a metal object highlights the potential of voltage-actuated liquid metals for material handling in dynamics of electrochemical settings.
Nor-Azman et al. (Sun,) studied this question.