Hydrogen bubble-templated electrodeposition of superhydrophobic Zn–Ni films

Abstract

When water droplets contact an unclean superhydrophobic surface, they roll on the surface taking away the dust. Herein, self-cleaning superhydrophobic Zn–Ni films were fabricated using a dynamic hydrogen bubble as the template. The influence of bath temperature on the surface topography, phase structures, and wettability was investigated. It turned out that, in the process of Zn–Ni films deposition, zinc was formed preferentially than nickel because Zn_ads⁺ promoted the reduction of zinc ions, which belonged to anomalous co-deposition. With an increase of the plating solution temperature, the bubble coverage on the films increased, and the water contact angles of the films increased first and then reduced. When the bath temperature was up to 40 °C, SEM observations revealed an even distribution of micropores on the surface and a rough, cauliflower-like cluster surface morphology, which facilitates superhydrophobicity. Thus, modifier-free superhydrophobic Zn–Ni films with a contact angle for water up to 152 ± 0.9° were achieved. The as-prepared superhydrophobic Zn–Ni films exhibited the plastron effect, stability against water jet impact, excellent self-cleaning properties, and anti-corrosion performance. It is believed that the superhydrophobic films can expand the application scope of magnesium alloys.