Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (07): 1764-1770.doi: 10.3866/PKU.WHXB201205112

• CATALYSIS AND SURFACE SCIENCE • Previous Articles     Next Articles

Promoted Effect of Polyethylene Glycol on the Photo-Induced Hydrophilicity of TiO2 Films

ZHENG Hua-Rong, WANG Xiao-Wei, LIN Xia-Hui, GENG Qiang, CHEN Xun, DAI Wen-Xin, WANG Xu-Xu   

  1. Fujian Provincial Key Laboratory of Photocatalysis——State Key Laboratory Breeding Base, Research Institute of Photocatalysis, Fuzhou University, Fuzhou 350002, P. R. China
  • Received:2012-03-21 Revised:2012-05-10 Published:2012-06-07
  • Contact: DAI Wen-Xin
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21073037) and National Key Basic Research Program of China (973) (2010CB234604).


To investigate the photo-induced hydrophilicity of TiO2 films and its durability, a series of TiO2 films containing polyethylene glycol (PEG) 2000 with different contents are prepared. The photo-induced hydrophilicity of the films is investigated by recording the water-droplet contact angle on the films? surface under UV irradiation, and the hydrophilicity durability is monitored under dark storage conditions. The photo-induced hydrophilicity of TiO2 films and its hydrophilicity durability are enhanced by introducing 2.0% (w) of PEG into the TiO2 sol. From Fourier transform infrared (FTIR) spectra and ultraviolet-visible diffuse reflection spectra (UV-Vis DRS), we infer that PEG acts as an electron donor to scavenge the photogenerated holes in TiO2 and promotes the formation of Ti3+ sites, which are induced by the Ti4+ sites accepting the photo-generated electrons of TiO2. This promotes the formation of hydrophilic sites (the surface hydroxyl species). Compared with the pure TiO2 film, the Ti3+ sites in the TiO2/PEG films are more stable, which prolongs the hydrophilicity of TiO2 films under dark conditions. This study is significant for the application of TiO2 as a self-cleaning material, and is also a facile approach to investigate the transient behaviors of TiO2 under UV irradiation.

Key words: Photo-induced hydrophilicity, Durability of hydrophilicity, Hole scavenger, TiO2 film, Ti3+ species, Polyethylene glycol