Low-temperature deposition of self-cleaning anatase TiO2 coatings on polymer glazing via sequential continuous and pulsed PECVD

Photocatalytic properties of semiconductor materials, studied now for decades, represent huge potentialities as environmentally friendly self-cleaning surfaces. Up to now, inexpensive and non-toxic TiO2-based photocatalysts remain the most interesting solution from practical and industrial point of view. Nevertheless, obtaining titania surface in its anatase phase, polymorph presenting the best photocatalytic property, usually requires high temperature. Hence, anatase containing self-cleaning titania coatings are still limited industrially to inorganic glazing. In this article, we present an innovative sequential deposition method using continuous and pulsed plasma enhanced chemical vapour deposition enabling the deposition of anatase photocatalytic thin films at substrate temperature below 60 degrees C. The morphology and crystalline structure of the TiO2 thin films deposited in both pulsed and continuous modes are investigated. Then, the combination of these two methods used sequentially successfully led to the deposition of self-cleaning TiO2 coatings on thick polycarbonate substrates without alteration, opening a new way for the deposition of photocatalytic coatings on thermolabile substrates such as organic glazing or lenses.