Condensation and densification mechanism of sol-gel TiO2 layers at low temperature

Titanium dioxide films were prepared by the sol-gel process at low temperature under dry and humid conditions. The effect of solution parameters on the solution reactivity was studied. Layers deposited on silicon wafers as well as on organic substrates were characterized by Fourier Transform infrared spectoscopy and ellipsometry. Their mechanical quality was also tested. Results reported in this paper demonstrate the influence of the temperature and humidity during post-deposition treatment on the network development and densification. A suitable balance between both mechanisms led to hard and flexible coatings compatible with the thermal expansion of polymer substrates.