Fabrication of a durable superhydrophobic surface with corrosion resistance on copper

In order to fabrication a durable superhydrophobic surface with corrosion resistance, we have constructed a copper oxide layer with a hierarchical structure in situ on the copper surface by using a chemical treatment. The corrosion resistance and superhydrophobic durability of the surface are enhanced due to the chemical stability of the oxide and the stability of the hierarchical structure. The surface morphology, composition and phase structure were characterized by SEM, EDS, XPS, FT-IR and XRD. The superhydrophobicity of the surface was investigated by wettability tests. The superhydrophobicity durability was investigated by acidic and alkaline solution contact angle test, water immersion test, and UV irradiation test. Electrochemical tests were conducted to examine the potentiodynamic polarization curves and electrochemical impedance spectra to investigate the corrosion resistance of the superhydrophobic specimen. The experimental results are as follows. The oxide formed by chemical treatment is CuO. In the oxide layer, the nano-needles are aggregated into bundles, and the bundles are intertwined with each other to form a stable pyramidal hierarchical structure. The superhydrophobic surface has a water contact angle of 160 degrees and a sliding angle of less than 2 degrees. The superhydrophobic surface is chemically stable. The contact angle is greater than 150 degrees for both acidic and alkaline test liquids. The superhydrophobic surface retains its hydrophobicity for a long time when immersed in water. After 20 days of exposure to UV light, the surface remains superhydrophobic. The superhydrophobic specimen has a low corrosion rate and high impedance. The superhydrophobic surface is corrosion resistant and can provide corrosion protection to the substrate.