Kazutaka Kamitani

Development of water-repellent glass improved water-sliding property and durability

A water-repellent glass with high water-sliding property using FAS for the hydrophobic material has been developed. It had been thought that the sliding property of FAS was inferior to PDMS. But it was found that the sliding angles of the surfaces coated with FAS were affected by coating condition. And the glass on which fluorinated alkyl groups oriented toward normal direction of the surface had almost equal water-sliding property to the one coated with PDMS. Furthermore its durability against wiper abrasion and outside weathering was much higher than that with PDMS. And XPS analysis was carried out to confirm the orientation of fluorinated alkyl groups on the developed water-repellent glass. This kind of water-repellent glass was adopted as commercial automotive windows.

Synthesis and spectroscopy of tpps-doped silica gels by the sol-gel process

Tetraphenylporphinetetrasulfonic acid (TPPS), which is well known as a photochemical hole-burning (PHB) dye, was incorporated in silica gels obtained by the sol-gel process from tetramethoxysilane (TMOS). The form of TPPS must be free base (H2P), which exists in basic condition, to be active in PHB. To obtain transparent and higher density silica gels doped with free-base TPPS, two-step hydrolysis processes using solutions containing NaOH were developed, and the gels having bulk density of about 1.5 g/cm3 were synthesized. The form of TPPS in the gels was investigated by measuring the absorption and luminescence spectra, and it was found that in the silica gels almost all the TPPS retained free-base form at the molar ratio of NaOH/TMOS above 10−3.

Synthesis and spectroscopy of TPP derivative-doped silica gels prepared by the sol-gel process

Abstract Tetrakis (4-sulfonatophenyl) porphyrin (TSPP) and terakis (N-methyl-4-pyridyl) porphyrin 4+ (TMPyP) which are well known as photochemical hole burning (PHB) dyes, were incorporated in silica gels obtained by the sol-gel process from tetramethoxysilane (TMOS). The hole-burning experiment was performed at 4.2 K. The hole-burning efficiency was quite lower for TSPP than for TMPyP. This result suggests the existence of PHB inactive or ineffective state for TSPP in the silica gel.

Synthesis and spectroscopy of organic dye-doped silica gels by sol-gel process

Tetraphenylporphinetetrasulfonic acid (TPPS), which is well known as a photochemical hole burning (PHB) dye, was incorporated in silica gels obtained by the sol-gel process from tetraethoxysilane (TEOS). The form of TPPS must be free base (H 2 P), which exists in basic condition, to be active in PHB. To obtain transparent silica gels doped with free-base TPPS, two-step hydrolysis processes using solutions containing NaOH were developed, by the spectroscopic investigation, it was found that in the silica gels almost all the TPPS retained free-base form at the molar ratio of NaOH/TEOS above 10 −3 , and that the dimerization of TPPS incorporated in the TEOS gels did not occur higher NaOH concentration than that in the TMOS gels.