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 °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°. 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.