Electrochemical Oxidation to Fabricate Micro‐Nano‐Scale Surface Wrinkling of Liquid Metals

Abstract Constructing wrinkled structures on the surface of materials to obtain new functions has broad application prospects. Here a generalized method is reported to fabricate multi‐scale and diverse‐dimensional oxide wrinkles on liquid metal surfaces by an electrochemical anodization method. The oxide film on the surface of the liquid metal is successfully thickened to hundreds of nanometers by electrochemical anodization, and then the micro‐wrinkles with height differences of several hundred nanometers are obtained by the growth stress. It is succeeded in altering the distribution of growth stress by changing the substrate geometry to induce different wrinkle morphologies, such as one‐dimensional striped wrinkles and two‐dimensional labyrinth wrinkles. Further, radial wrinkles are obtained under the hoop stress induced by the difference in surface tensions. These hierarchical wrinkles of different scales can exist on the liquid metal surface simultaneously. Surface wrinkles of liquid metal may have potential applications in the future for flexible electronics, sensors, displays, and so on.