title: Imaging of Hydrophilicity and its Inhomogeneity on a Titanium Dioxide Film Exposed to Ultraviolet Irradiation Using a Newly Developed Near-Infrared Camera.
abstract: This study has investigated hydrophilicity changes and their inhomogeneity of TiO2 films on Pyrex glasses by near-infrared (NIR) spectral imaging. Near-infrared spectra of TiO2 films in the 9000-4000 cm(-1) region were measured using a newly developed NIR camera named Compovision. A band in the 5400-4800 cm(-1) region, which is assigned to a combination (ν2 + ν3) mode of bending (ν2) and antisymmetric stretching (ν3) modes of the H2O molecule, was clearly identified and its intensity increased with time in the air. It is interesting that the increased rate rose with ultraviolet (UV) light irradiation (300-400 nm, 1 mW cm(-2)) compared to without UV light irradiation. This result suggested that the hydrophilicity of TiO2 was enhanced about twice upon the UV light irradiation. Moreover, the NIR images clarified spatial distributions of the hydrophilicity on the TiO2 surface with a significantly wide area (20 × 40 mm) and a high speed (within 5 s for one image). This rapid imaging system enabled us to detect the hydrophilicity change during only 1 min. The potential of this camera is quite superior, not only for basic research, but also for diverse industrial applications.
authors.affiliation: Kwansei Gakuin University, Department of Chemistry, School of Science and Technology, 2-1 Gakuen, Sanda 669-1337, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Tanabe
authors.forename: Daitaro
authors.initials: D
authors.lastname: Ishikawa
authors.forename: Daiki
authors.initials: D
authors.lastname: Furukawa
authors.forename: Mika
authors.initials: M
authors.lastname: Ishigaki
authors.forename: Takeyoshi
authors.initials: T
authors.lastname: Goto
authors.forename: Tetsu
authors.initials: T
authors.lastname: Morishima
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Okuno
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Ozaki