Study on functional properties of cotton fabrics using an environmentally friendly deposition of TiO2 nanoparticles

TiO2 nanoparticles (TiO2-NPs) are widely used in textiles to block UV (ultraviolet) radiation, self-cleaning, and even bactericidal action. In this work, TiO2-NPs were deposited on cotton fabrics through high-intensity (kV) and short-period (µs) pulsed electrical discharges submerged in an aqueous medium. No chemical reagents were added as a binder, and no pre-treatment was applied to the fabric. After the nanoparticle deposition, the samples were submitted to 10 washing cycles. The samples were characterized through thermogravimetry and field emission-gun-scanning electron microscopy (FEG-SEM) to evaluate nanoparticle distribution and adhesion. The results show a high surface density of nanoparticles (NPs) along the fibers, containing approximately 7% by weight of TiO2-NPs, even after the washing cycles. By the method proposed TiO2-NPs deposition increased UV radiation blocking, especially in the UVB region, from 77% (Pristine) to 98%, reaching a UPF of 50 + for the unwashed treated samples and UPF over 40 after 10 washing cycles. Both treated and untreated samples showed partial discoloration of white stains after a 24 h exposure to UV radiation, resulting in a more pronounced discoloration and less yellowing in treated samples. No bactericidal action was observed in samples coated with TiO2-NPs in microbiological tests of the bacterium S. aureus, even after photoactivation.