Is electric field always a promoter of wetting? Electro-dewetting of metals by electrolytes probed by the in situ X-ray nanotomography
We developed a special electrochemical cell enabling quantitative analysis and the in situ X-ray nanotomography of metal/electrolyte interfaces subject to corrosion. Using this cell and applying the nodoid model to describe menisci formed on tungsten wires during anodization, the evolution of the electrolyte surface tension, the concentration of reaction products, and the meniscus contact angle were studied. In contrast to the electrowetting effect when the applied electric field decreases the contact angle of electrolytes, anodization of the tungsten wires increases the contact angle of meniscus. Hence, electric field favors dewetting rather than wetting of the newly formed surface. The discovered effect opens up new opportunities for the control of wetting phenomena and calls for revision of the existing theories of electrowetting.