Fabrication of superhydrophobic vanadium pentoxide nanowires surface by chemical modification

Vanadium pentoxide (V2O5) nanowires have been synthesized on Au-coated Si substrates by a physical vapor deposition process. The synthesized nanowires are randomly oriented with a diameter around 40–200 nm and length of several micrometers. The crystalline structure of the nanowires analyzed by using X-ray diffraction and Raman spectroscopy corresponds to single crystalline orthorhombic V2O5 phase with [0 0 1] growth orientation. The transmission electron microscopy and energy-dispersive X-ray analysis suggests a possible vapor–solid (VS) growth mechanism for the V2O5 nanowires. A self-assembled monolayer (SAM) of octadecyltrichlorosilane (OTS) was deposited on the V2O5 nanowires to obtain superhydrophobic V2O5 nanowire surfaces with water contact angle (CA) of 157.5°. The superhydrophobic behavior is attributed to the high surface roughness provided by the nanowire surface and low surface energy due to SAM layer deposition. The impact dynamics of water droplets impinging on the superhydrophobic surface is also investigated.