TiO2 mesoporous thin films studied by Atmospheric Ellipsometric Porosimetry: A case of contamination

in Microporous & Mesoporous Materials (2011), 147

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the ... [more ▼]

Anatase mesoporous TiO2 thin films are frequently prepared by surfactant templating to control porosity development and Atmospheric Ellipsometric Porosimetry is a reliable and fast technique allowing the determination of the porosity of such films. After prolonged exposition to high-vacuum (6×10-6 mbar), the films porosity exhibits a degraded behavior during porosimetric measurements, indicating a vacuum-induced modification. The main effect resulting from such exposition to high-vacuum is a wet- tability modification of the films, resulting in an increase of the hydrophobic character of the TiO2 surface. This evolution induces non-correct results in porosimetric measurements due to the fact that the contact angle parameter needed to calculate the pore size distribution is highly different from the reference films. A surface contamination explains such modifications and a restoration of the films is obtained by using ultraviolet treatment. [less ▲]