Preparation and properties of nano-TiO₂/SiO₂ composite sol-modified cotton fabrics

The growing demand for eco-friendly and multifunctional textile finishings led to significant attention being placed on sustainable water repellent, ultraviolet (UV)-protective, and self-cleaning agents. In this study, a TiO₂/SiO₂ composite sol was prepared via the sol–gel method and applied to cotton fabric surfaces, thereby endowing textiles with superhydrophobic, anti-UV, and self-cleaning functionalities. X-ray photoelectron spectroscopy confirmed the formation of robust covalent bonds (C–O–Ti and C–O–Si) between the coating and the cotton substrate, contributing to an excellent washing durability. The composite sol formed a uniform micro/nanostructured coating, significantly enhancing the hydrophobicity with a water contact angle of 151.8°, which only slightly decreased to 143.9° after 50 washing cycles. Additionally, the UV protection factor rose from 15.58 to 116.7, and the self-cleaning function (enabled by the photocatalytic activity of TiO₂) was enhanced by SiO₂ through suppressed electron–hole recombination. Despite minor reductions in the whiteness and air permeability characteristics, the introduced coating led to an enhanced colour fastness and shrinkage resistance. Overall, this work provides an effective strategy for durable and eco-friendly textile surface functionalization to produce materials that are suitable for outdoor protective and architectural applications.