Aqueous sol–gel synthesis and film deposition methods for the large-scale manufacture of coated steel with self-cleaning properties

Abstract

A process has been developed to enable the large-scale production of pure TiO₂ films deposited on 316L stainless steel in order to get an easy-to-clean surface. This large-scale process requires an easy aqueous sol–gel procedure for the synthesis of the TiO₂ sol. This synthesis has been simplified to facilitate the extrapolation toward an industrial scale. Results of TEM, photocatalytic properties, film hydrophilicity and texture obtained with the simplified aqueous sol–gel synthesis (IsoP–TiO₂ synthesis) show similar properties to those obtained with the standard aqueous sol–gel synthesis of TiO₂ (HAc–TiO₂ synthesis) developed previously. Only, X-ray diffraction patterns showed differences, with the presence of anatase-brookite phases in IsoP–TiO₂ synthesis while anatase phase only was observed in HAc–TiO₂ synthesis. Both the aqueous sol–gel synthesis of pure TiO₂ and the film deposition on steel by roll-coating have been successfully extrapolated to a larger scale. The photocatalytic activity and the hydrophilicity of the film were found to be unchanged when compared to films produced at a laboratory scale, thus validating the production of an efficient easy-to-clean material. Although some problems are still to be solved, this study is a hopeful first step in the development of a large-scale process for self-cleaning steel production.

Graphical Abstract