Fabrication of CuZn ₅-ZnO-CuO micro-nano binary superhydrophobic surfaces of Cassie-Baxter and Gecko model on zinc substrates

Superhydrophobic surfaces were prepared via immersing the clean perpendicular zinc substrates into aqueous copper chloride (CuCl ₂) solution and followed by annealing in dry air. Two Superhydrophobic models were obtained by controlling the concentration of CuCl ₂ aqueous solution. One had a high water contact angle (CA) of 162 ± 2°with a small sliding angle SA of less than 2 ± 1°, which was identified with Cassie-Baxter model, the other had a high CA of larger than 150°with a high adhesion, which was identified with Gecko model. CuZn ₅-ZnO-CuO micro-nano binary structure leads to superhydrophobicity of the surface. Wettability and durability of surfaces were investigated and a theoretical explanation on superhydrophobic surfaces is presented. Durability test was carried out to study properties of the surface. Formation mechanism of the surface was also explained.