Surface modification of TiO₂/SiO₂ composite hydrosol stabilized with polycarboxylic acid on Kroy-process wool fabric

Self-cleaning of wool fabric has been of increasing interest due to availability and practicability. In this paper, two kinds of wool fabrics, including raw wool and Kroy-process wool fabric, were successfully modified by TiO2/SiO2 gel stabilized by 1,2,3,4-butanetetracarboxylic acid (BTCA) and citric acid (CA), respectively. The optimum concentration of carboxylic acids and TiO2/SiO2 gel was decided by the crease recovery angles and total color difference (ΔE) values, respectively. The results revealed that wool fabrics treated with BTCA and TiO2/SiO2 had better wrinkle resistance in comparison with CA and TiO2/SiO2 treated samples. The decomposition of stains was studied using UV irradiation and the presence of TiO2/SiO2 gel demonstrated obvious self-cleaning property, in which the color of wool fabric was unchangeable. The hydrophilicity of Kroy-process wool fabric increased relative to raw ones. In addition, Scanning Electron Microscope images demonstrated the layer of TiO2/SiO2 nanoparticles coated on treated samples. In general, the adhesion properties coated to the fabric surface showed a slight loss even at harsh processing conditions, however, the anti-UV properties obviously increased due to the decrease in the fabric porosity. And the linkages between carboxylic acid and wool fibers were illustrated using FTIR pattern.