Smart surfaces for architectural heritage: Preliminary results about the application of TiO2-based coatings on travertine

The development and application of self-cleaning treatments on historical and architectural stone surfacescould be a significant improvement in conservation, protection and maintenance of CulturalHeritage. In this paper, a TiO2-based coating has been investigated in order to evaluate its possible use as aself-cleaning treatment. This coating was obtained by a sol-gel and a hydrothermal (134 ◦C) processes andthen it was applied on travertine (a limestone often used in historical and monumental buildings) in twoways, obtaining a single-layer and a three-layer treatment, respectively. In order to verify its potentialuse in the field of Cultural Heritage, the maintenance of appearance properties of the treated travertinesurfaces was monitored by colour and gloss analyses. Besides, de-pollution and soiling removal testswere carried out under ultraviolet-light exposure to evaluate photo-induced effects and self-cleaningefficiency. Results seem to allow the use of TiO2-based treatments on historical and architectural surfacesmade up by travertine, where de-pollution and self-cleaning photo-induced effects are well evident,maintaining their original visual appearance. Anyway, before applying TiO2-based coatings as conservativetreatments, further tests are needed especially on their durability, that is mandatory for CulturalHeritage applications. On-site test in an urban environment and accelerated test by weatherometer arecurrently under way.