Microstructure of sol-gel derived TiO2 thin films characterized by atmospheric ellipsometric porosimetry

Adsorption of water vapor during ellipsometric measurements was performed in-situ for the characterization of sol-gel derived TiO₂ thin films. The data obtained were compared with complementary results derived from scanning electron microscopy and photocatalytic degradation measurements. Results indicate that a less permeable surface layer encapsulates the porous interior of the films which may become more accessible by defects such as cracks. Atmospheric ellipsometric porosimetry provides a valuable tool for the microstructural characterization of sol-gel films.