Stable superhydrophobic Zn/ZnO surfaces fabricated via electrodeposition on tin substrate for self-cleaning behavior and switchable wettability

Superhydrophobic Zn/ZnO coatings on tin substrate with irregular polyhedral structure are grown via electrodeposition combined with anneal. The resultant surfaces deposited at −1.6 V for 10 min and annealed at 200 °C for 10 min show good superhydrophobicity, exhibiting a water contact angle of 160° and a sliding angle of about 1°, showing excellent rolling-off and self-cleaning properties. The influence of ultrasonic treatment on film thickness, wetting property, surface morphology and composition were systematically researched to understand the growth mechanism of the superhydrophobic Zn/ZnO film. The superhydrophobic stability of the Zn/ZnO surfaces were investigated by the means of exposure to the air, buried in soil, harsh mechanical bending and water jet impacting. The reversibly switchable wettability between superhydrophobicity and superhydrophilicity of the Zn/ZnO surface were studied by alternate UV irradiation and heating. The discoveries in this work provide an economic and simple route to fabricate versatile superhydrophobic surfaces on conductive substrates, which has excellent promise for future applications.