Optimum conditions for fabricating superhydrophobic surface on copper plates via controlled surface oxidation and dehydration processes

Both the oxidation conditions and the modification conditions were optimized. The prepared surfaces on copper substrate show different wettability, which mainly arises from different morphologies. •The copper-based superhydrophobic surfaces were fabricated by controlled oxidation.•The oxidation conditions including the concentrations and time were optimized.•Effects of modification conditions were investigated.•The optimal conditions for the best superhydrophobicity were obtained.•The surface microstructure and composition were characterized and analyzed. The superhydrophobic surfaces on copper substrate were fabricated by direct oxidation and dehydration processes, and the reaction and modification conditions were optimized. Firstly, the oxidation conditions including the concentrations of K2S2O8 and NaOH, the oxidation time were studied. It is found that the superhydrophobicity would be better if the copper plates were oxidized in 0.06MK2S2O8 and 3.0M NaOH solution at 65°C for 35min. Then, the modification conditions including modifier concentration and modification time were investigated. The results showed that 5wt% lauric acid and 1h modification time were suitable modification conditions for preparing copper-based superhydrophobic surfaces. The surface fabricated under optimized conditions displayed excellent superhydrophobicity of high water contact angle of 161.1° and a low contact angle hysteresis of 2.5°. The surface microstructure and composition of the superhydrophobic surfaces were also characterized by SEM and FT-IR. It is found that the highly concentrated micro/nanostructured sheets and the low surface energy materials on the surface should be responsible for the high superhydrophobicity.