Self-cleaning of wool-polyamide and polyester textiles by TiO2-rutile modification under daylight irradiation at ambient temperature

This study presents radio frequency plasma (RF-plasma), microwave plasma (MW-plasma), and vacuum-UV light irradiation as pretreatment of synthetic textile surfaces allowing the loading of TiO2 by wet chemical techniques in the form of transparent coatings constituted of nano-particles of diverse sizes. These loaded textiles show a significant photo-oxidative activity under visible light in air under mild conditions, which discolors and mineralizes persistent pigment stains contained in wine and coffee. The mineralization of stains on the textile loaded with TiO2 was monitored quantitatively to assess the appropriate surface pretreatment in conjunction with the most suitable deposition method of TiO2 colloids, powders, or combination of both. Their photocatalytic activity allowed, in kinetically acceptable times, the almost complete discoloration of coffee and wine stains. The observed discoloration of colored stains seems to involve visible light sensitization of the stain pigment on the TiO2-loaded textile. The size of the particles obtained from colloidal precursors of TiO2 varied between 5 and 25 nm.