SiO 2 -TiO 2 Nanostructure Films on Windshields Prepared by Sol-Gel Dip-Coating Technique for Self-Cleaning and Photocatalytic Applications

Abstract

In the present research, automotive windshield samples were successfully coated with SiO 2 -TiO 2 nanostructure layer using the sol–gel technique for self-Cleaning and photocatalytic applications. This procedure resulted in transparent, crack-free, self-cleaning, nanostructure SiO 2 –TiO 2 films. To prevent the thermal diffusion of the sodium ions from the glass substrate to TiO 2 layer, the SiO 2 layer was pre-coated on the glass by the sol–gel method. The coated samples were dried for 48 hour at room temperature to allow slow solvent evaporation and condensation reactions due to rapid sol–gel reaction of titania precursor. Then, the samples were annealed at 100℃ for 30 min and at the final temperature (500℃ and 700℃) for 30 min immediately. The crystalline structure, surface morphology, photocatalytic activity and hydrophilic properties of the films were investigated using XRD, SEM, FE-SEM, UV–Vis spectrophotometer and contact angle measurement, respec-tively. The FE-SEM surface morphology results indicate that the particle size increases from 19 to 42 nm by increasing the annealing temperature from 500℃ to 700℃. Likewise, XRD illustrate the crystal anatase and rutile as main phases for SiO 2 -TiO 2 films annealed at 500℃ and 700℃, respectively. Increasing heat treatment temperature from 500 to 700℃, de-creases the photocatalytic activity and inversely increases of the contact angle of the films.