Self-cleaning cotton fabrics via combination of photocatalytic TiO2 and superhydrophobic SiO2

Abstract

Fluorine-free superhydrophobic cotton fabrics with photocatalytic self-cleaning property were prepared by the combination of photoactive TiO2 and superhydrophobic SiO2. Organically modified silica (ormosil) aerogel with a high surface area and high porosity was first prepared. TiO2 nanocrystals were then synthesized and simultaneously deposited onto preformed porous ormosil aerogel at low temperature (below 100°C) to obtain TiO2–SiO2 composite particles. XRD measurements prove that the formed TiO2 is of anatase phase. SEM and TEM images disclose the highly porous structure of the TiO2–SiO2 composite particles and further confirm the existence of highly crystalline TiO2 within the SiO2 matrix. IR spectra indicate the presence of abundant methyl groups on the TiO2–SiO2 composite particle surface. BET measurements show a high surface area of 379.0m2/g for the TiO2–SiO2 composite particles, which is advantageous to enhance the photocatalysis. The cotton fabrics coated with TiO2–SiO2 composite particles exhibit superhydrophobicity with a water contact angle of 160.5°. However, the superhydrophobic cotton fabrics can be easily wetted by oil dirt and become superhydrophilic. Herein, the TiO2–SiO2 composite particle coated cotton fabric, which was contaminated with oleic acid, can recover its superhydrophobicity after UV irradiation for 4h.