In this work, a superhydrophobic material was successfully prepared with a water contact angle of about 155.5° and a rolling-off angle of about 6.8°, which showed superior UV resistance (365 nm, 5.0 ± 0.6 mW cm⁻²) for an illumination period of 30 h. The degradation of organic dyes, such as Nile red, methyl blue and orange, could be also achieved with our prepared surface. Anti-UV water-repellency was combined with photocatalysis to realize a self-cleaning surface for both dirt removal and organic degradation. Moreover, the reversible changes with superhydrophobicity and superhydrophilicity were induced by the self-healing property on such a surface, contributing to heavy and light oils/water separation. Because of ultra-long UV-resistance, photocatalysis, self-cleaning, self-healing and oil/water separation functions, our reported surface has potential for application in a variety of fields.

We report a one-step corrosion process to synthesize nanostructured CuO thin films at room temperature. The reaction time has great effect on the composition and microstructure of products to control the size and shape of the copper compound. X-ray diffraction studies showed the transformation of nanograins from Cu(OH)₂ nanowires to flower-like CuO and to dispersed CuO nanosheets. The optical properties of CuO nanosheets were investigated by using UV-vis spectroscopy with considerable blue-shift in the optical band gap (E_g = 1.8 eV) due to the quantum confinement effect. Additionally, the photocatalytic activities of as-prepared copper compound films were determined by measuring the degradation of methyl blue (MB) to find out their potential application in waste water treatment. The photoluminescence (PL) spectrum showed both UV as well as visible emission peaks, indicating their good optical properties. Moreover, a reasonable growth mechanism for the formation of the CuO nanostructure is proposed by means of a scanning electron microscope (FESEM).