TiO2 optical coating layers for self-cleaning applications

TiO2 films deposited by various coating techniques were investigated for self-cleaning applications. The optical coating layers of TiO2 films prepared from a sol–gel precursor were deposited on glass substrates using spin coating, dip coating and screen printing techniques. Effects of film deposition techniques on crystal structure, microstructure, thickness, photocatalytic activity, hydrophilicity and optical properties of the films were investigated using XRD, AFM, SEM, surface profilometer, UV–vis spectrophotometer and contact angle measurement. Dip coating the TiO2 optical film two and three times resulted in superhydrophilic surfaces. Increasing number of dipping times was found to increase the photocatalytic activity.