Abstract: SiO2/TiO2 composite sol was prepared with tetraethoxysilane (TEOS) and tetrabutyl titanate (TBT), and it was coated on cotton fabric to present hydrophobic-hydrophilic switchable property via UV response. The contact angle of the coated fabric was 121.3° and was hydrophobic, but after radiated in UV for 18h, the contact angle was 0° and was hydrophilic. When the radiated fabric was kept in dark place for 12h, the contact angle was increased to 93.2° from 0°. When the fabric was in UV and dark place for 10 times, the contact angle was kept in between 0° and 92°-96°, and showed hydrophobic-hydrophilic switchable property. From the ultraviolet spectrum, the ultraviolet radiation transmittances of the coated fabrics were decreased slightly via radiation UV for 18h, whereas, the ultraviolet radiation transmittances were increased when the radiated fabric was kept in dark place for 12h, and this changes of the ultraviolet radiation transmittances verified the mechanism of switchable wettability.

Key words: sol-gel technology, wettability, UV response, contact angle, cotton fabric