H. Imai et al., Alternative modification methods for sol-gel coatings of silica, titania and silica-titania using ultraviolet irradiation and water vapor, THIN SOL FI, 351(1-2), 1999, pp. 91-94
We investigated relatively new techniques for densification and crystalliza
tion of sol-gel silica, titania and silica-titania coatings at relatively l
ow temperatures. irradiation of ultraviolet photons above the band-gap ener
gy was found to lead shrinkage of the sol-gel films through electronic exci
tations. Crystallization of sol-gel titania coatings was achieved by irradi
ation of ultraviolet laser (4.7 eV) beam. Exposure to water vapor was shown
to be effective in rearrangement of sol-gel films causing densification of
silica, crystallization of titania and phase separation of silica-titania
around 100 degrees C. These techniques are useful for preparation of hard s
ilica coatings and crystalline titania films on low-heat-resistant substrat
es, such as polymer plates. (C) 1999 Elsevier Science S.A. All rights reser
ved.