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The antibacterial activity of photocatalytic titanium dioxide (TiO 2 ) thin films with photodeposited silver on the surface of sanitary ware was studied. Samples were prepared by coating a TiO 2 sol that was calcined at 8801-9801C and photodeposited with silver ions onto the glazed layer of the sanitary ware. The relationships between the antibacterial activity and the fabrication conditions were investigated by X-ray diffractometry, scanning electron microscopy, and colorimetry. The phase of TiO 2 identified in the thin films was a mixture of anatase and rutile. The amount of rutile phase increased as the calcination temperature increased, and grain growth of the TiO 2 particles was observed. The activity was dependent on the TiO 2 thickness, the calcination temperature, and the amount of silver. These results suggest that the antibacterial activity was strongly affected by the amount of anatase in the thin films. 9801C for 1 h in a muffle furnace (Model FP-31, Yamato Science Company, Ltd., Tokyo, Japan). Sample tiles with a TiO 2 thin-film coating on the glaze were obtained. 95J ournal

Super-hydrophilic titanium dioxide (TiO 2 ) photocatalysts with some mild oxidizing ability are favorable for the self-cleaning applications on plastic films. In this study, we have focused on brookite TiO 2 for such purposes. Brookite TiO 2 powders were synthesized by the hydrothermal conversion method using Mg 2 TiO 4 as a precursor. Mg 2 TiO 4 (1 g) and 1 M HCl (30 mL) were put into a polytetrafluoroethylene (PTFE)-lined autoclave. The hydrothermal conversion was conducted at 110150°C for 24 h. The photocatalytic oxidizing properties of brookite TiO 2 /silicone films on glass substrates, prepared by the flow-coating method, were measured by methylene blue decomposition, and the photo-induced hydrophilicizing properties were evaluated using the contact angle of water under UV irradiation. The brookite TiO 2 /silicone film prepared from the sample treated at 150°C exhibited well-balanced properties for self-cleaning applications.

Polyethylene-terephthalate (PET) films coated with photocatalytic TiO 2 and silicone as a binder were fabricated and attached to a window pane. A white substance was observed on the surface after exposure for several months in an area with air pollution. The white substance was analyzed by scanning electron microscopy and energy dispersive X-ray spectroscopy, ion chromatograph and capillary electrophoresis, and was identified as CaSO 4 . Although the oxidizing properties of the films were affected by the particle size and the amount of TiO 2 in the photocatalytic layer, the hydrophilicizing properties of the films were hardly changed by them. In this study, we found that it was possible to decrease the oxidizing properties of photocatalytic PET films while maintaining the hydrophilicizing properties constant by using small TiO 2 particles and controlling the ratio of TiO 2 /binder.

The synthesis of pure brookite is generally much more difficult than that of pure anatase. The hydrothermal conversion, recently developed by Kozawa et al., is a facile method to synthesize brookite TiO 2 from inverse spinel-type Mg 2 TiO 4 under a mild hydrothermal condition e.g. in 1 M HCl solution at 100°C. However, slight rutile TiO 2 is usually co-existed under the reported conditions. The aim of this study is to prepare a high-purity brookite TiO 2 powder by the