A facile method to fabricate superhydrophobic ZnO nanostructure with petal effect

ZnO nanostructures were fabricated on glass substrate through a convenient deposition process. Firstly, ZnO seed layers were deposited on glass substrates through sol–gel method. Secondly, the ZnO nanostructures were then grown in a Teflon-lined stainless steel autoclave by immersing the seed layers into aqueous solution containing zinc nitrate hexahydrate and ammonia. The microstructures, morphologies, photoluminescence spectra and hydrophobicity of the nanostructures were analyzed by X-ray diffraction spectrometer, field emission scanning electron microscopy, laser micro-Raman spectrometer and contact angle apparatus, respectively. It can be seen that ZnO nanostructures display different surface morphologies such as ZnO nanorods parallel to the substrate surface, like-pencil ZnO nanorods and bending ZnO nanorods by altering the PH value. The largest intensity ratio of the UV/visible emission and the superhydrophobic surfaces (CA = 156°) with high adhesion can be achieved in the sample grown in the solutions with the PH value of 11.2. The high adhesion may be attributed to the strong capillary force and the ZnO nanostructures with petal effect can be explained by Wenzel model.