Effects of thermal and evacuating treatments on photo-induced hydrophilic conversion at TiO2 surfaces

被引:9
作者
Minabe, T
Fujishima, A
Nakajima, A
Watanabe, T
Hashimoto, K
机构
[1] Univ Tokyo, Adv Sci & Technol Res Ctr, Meguro Ku, Tokyo 1538904, Japan
[2] Univ Tokyo, Sch Engn, Dept Appl Chem, Bunkyo Ku, Tokyo 1138656, Japan
关键词
hydrophilicity; contact angle; titanium dioxide;
D O I
10.5796/electrochemistry.68.779
中图分类号
O646 [电化学、电解、磁化学];
学科分类号
081704 ;
摘要
It is well known that the amount of physisorbed water molecules decreases by thermal and evacuating treatments at anatase TiO2 surfaces. (1- 3)) However, the initial water contact angle of the anatase TiO2 surface coated on the glass was little changed (from 24 degrees +-/ 1 degrees to 23 degrees +/- 1 degrees) and the hydrophilicity did not change by the heating treatment at 150 degreesC for 1 hour. On the other hand, the value of its initial contact angle increased remarkably (from 24 degrees +/- 1 degrees to 67 degrees +/- 1 degrees), and the TiO2 surface was hydrophobicized by the evacuation at similar to 5x10(-6) Pa. These observations may show that not only the amount of physisorbed water molecules but also the structure, i.e., OH groups of TiO2 surfaces are related to the hydrophilicity. The photo-decreasing rate of the water contact angle under the ultra violet (UV) illumination at the anatase TiO2 surface (the photo-induced hydrophilic conversion rate) increased by the heating treatment at 150 degreesC for 1 hour. However, photo-induced hydrophilic conversion rates were little changed by the evacuating treatment at similar to 5x10(-6) Pa. These results suggest that the photo-induced hydrophilic conversion phenomena are not necessarily affected by the initial amount of physisorbed water molecules.
引用
收藏
页码:779 / 782
页数:4
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