Wettability, Photoactivity, and Antimicrobial Activity of Glazed Ceramic Tiles Coated with Titania Films Containing Tungsten

ONNA, DIEGO; FUENTES, KEYLA M.; SPEDALIERI, CECILIA; PERULLINI, MERCEDES; MARCHI, MARÍA CLAUDIA; ALVAREZ, FERNANDO; CANDAL, ROBERTO J.; BILMES, SARA A.

ACS Omega

American Chemical Society

Año: 2018 vol. 3 p. 17629 - 17636

Self-cleaning coatings are advanced materials for the removal of pollutants and microorganisms by combining wettability, photocatalytic degradation, and antimicrobial activity. In this work, we propose a rational design of self-cleaning films based on TiO 2 synthesized by sol-gel on commercial glazed ceramic tiles for building´s indoor applications. The synthesis strategy is based on hydrolysis and condensation of Ti-isopropoxide in the presence of W(VI) precursors to tune defects and crystallinity of the resulting W-TiO 2 thin film. From the microstructure and surface composition analysis for different tungsten contents and annealing temperatures, we conclude that the film is composed by sintered TiO 2 particles with adsorbed polytungstates (WO x ) that inhibit anatase/rutile transformation. Polytungstates on TiO 2 also induce surface defects that enhance water contact angle and inactivation of Escherichia coli under visible light. The presence of W(VI) has a negligible effect toward crystal violet degradation either under visible or under UV light. These results provide evidence on the existence of at least two different types of defects: (i) intrinsic defect from a sol-gel route and (ii) induced defect by tungsten species on the surface. Understanding the correlation between composition, structure, and self-cleaning properties provides a base for an efficient design of low-cost self-cleaning ceramic tiles that can be fully manufactured in an industrial plant.