Conversely, a water drop placed on the coating prepared from silica sol (solution B) was immediately spread and wets the surface completely with water contact angle measured less than 101. The silica coating sol prepared from sol–gel
processing of TEOS contains no hydrocarbon groups and the hydrolysis and condensation of all four
ethoxy group's results into the hydroxyl terminated silica surface. Due to the inherent hydrophilic
characteristics of silica, the water drops spread out on the surface with very low contact angle [21].