| STUDY |
Wettability of TiO2 reexamined New results from an investigation of titania's surface properties call into question recently proposed mechanisms for TiO2's photo-induced wettability. Motivated by TiO2's usefulness in a range of applications, such as self-cleaning windows and self-sterilizing surfaces, researchers have tried to develop methods for controlling the material's hydrophilicity (wettability). The work has led to the observation that irradiation with UV light increases hydrophilicity. Various researchers have proposed that the increase is a result of radiation-induced changes in the concentration and structure of surface-bound OH groups. Others have proposed explanations that depend on oxygen vacancies or on photogenerated electrons trapped at Ti3+ surface sites. But those explanations may need to be reevaluated based on a study conducted by Michael A. Hen- derson and Janos Szanyi of Pacific Northwest National Laboratory and J. M. (Mike) White, a chemistry professor at the University of Texas, Austin. The group finds that water wets clean TiO2 surfaces regardless of whether or not the surfaces are marked with oxygen vacancies and Ti3+ ions [J. Phys. Chem. B, published online July 29, http://dx.doi.org/10.1021/jp0345046]. Likewise, dissociation of water to form surface OH groups is not required for water to wet the surface, they say. |
|
Want more information ? Interested in the hidden information ? Click here and do your request. |