[en] Easy-to-clean surfaces can be obtained by the deposition of thin coatings presenting either superhydrophilic or superhydrophobic properties. A wide range of coatings and associated deposition technologies has been studied in the past years to elaborate such kind of coatings and promote surface cleaning by water. When considering industrial use, some important criteria must be taken into account including ease of processing and speed, coating robustness and durability, aesthetic, product toxicity and cost.
This presentation deals with the elaboration at industrial scale of hydrophilic easy-to-clean and anti-staining layers on prepainted steel. This metallic material, used for building applications, is sensitive to environmental fouling occurring over the time and leading to inaesthetic dirtying of the surface. The solution studied in this work is based on a nanometric coating constituted of SiO2 which increases surface hydrophilicity and prevents from dust embedding in the paint. Thanks to the combination of these effects, the preservation of the initial surface aspect is highly improved over the time. Moreover, when an anatase TiO2 top layer is deposited on the SiO2 coating, an additional photocatalytic effect can be measured. Both SiO2 and TiO2 layers are deposited from aqueous colloidal solutions that fit with industrial requirements and tools.
Their properties are described in term of easy-cleaning and anti-staining effects through water contact angle measurements, accelerated staining tests and natural outdoor exposure, on prototypes elaborated at industrial scale in a roll-to-roll process. The coating robustness and the durability of the properties are validated after accelerated ageing tests, including corrosion and UV resistances, and after mechanical deformation.
Disciplines :
Materials science & engineering Chemistry Chemical engineering
