Direct synthesis of superhydrophobic silica nanowires surface by evaporating ZnS on silicon wafer

Silica nanowires (SiO2-NWs) were successfully synthesized on a large scale by direct thermal evaporation of ZnS powder on silicon wafer at 1350 degrees C. The special geometric morphology induced a high surface roughness (root-mean-square) of several hundreds of nanometers. After functionalization with perfluoroalkysilane (FAS), the SiO2-NWs surface showed a superhydrophobic property with the highest water contact angle greater than 148 degrees. The uneven surface with high roughness and the generated C-F chains by chemical modification contributed to the improved superhydrophobicity. The superhydrophobic SiO2-NWs surface can be applied as a self-cleaning material to remove dirty particles in many fields.