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

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

ACS Omega

American Chemical Society

Lugar: Nueva York; Año: 2018 vol. 3 p. 17629 - 17636

2470-1343

ABSTRACT: Self-cleaning coatings are advanced materials for the removal ofpollutants and microorganisms by combining wettability, photocatalyticdegradation, and antimicrobial activity. In this work, we propose a rationaldesign of self-cleaning films based on TiO2 synthesized by sol−gel oncommercial glazed ceramic tiles for building?s indoor applications. Thesynthesis strategy is based on hydrolysis and condensation of Ti-isopropoxidein the presence of W(VI) precursors to tune defects and crystallinity of theresulting W−TiO2 thin film. From the microstructure and surface compositionanalysis for different tungsten contents and annealing temperatures, weconclude that the film is composed by sintered TiO2 particles with adsorbedpolytungstates (WOx) that inhibit anatase/rutile transformation. Polytungstateson TiO2 also induce surface defects that enhance water contact angleand 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 tilesthat can be fully manufactured in an industrial plant.