Fabrication and properties of superhydrophobic SiO2 thin film by sol-gel method

Superhydrophobic thin films were successfully fabricated on a glass substrate by sol-gel method. To fabricate thin film with a high roughness, nano particles were added into tetraethoxysilane (TEOS) solution. The prepared thin film without an addition of nano particles showed a very flat surface with ca. 1.27 nm of root mean square (RMS) roughness. Otherwise, the thin films fabricated by using coating solutions added nano particles of 1.0, 2.0 and 3.0 wt% showed a RMS roughness of ca. 44.10 nm, ca. 69.58 nm, ca. 80.66 nm, respectively. To modify the surfaces of thin films to hydrophobic surface, a hydrophobic treatment was carried out using a fluoroalkyltrimethoxysilane (FAS). The thin films with a high rough surface were changed from hydrophilic to hydrophobic surface after the FAS treatment. Especially, the prepared thin film with a RMS roughness of 80.66 nm showed a water contact angle of .