Spontaneous formation of linear striations and cell-like patterns on dip-coating titania films prepared from alkoxide solutions.
Linear striations and cell-like patterns were spontaneously formed on the dip-coating titania films prepared titanium tetraisopropoxide (Ti(OC(3)H(7)(i))(4)) solutions. Such unique patterns on micrometer scale were arranged parallel to the substrate withdrawal direction. The values of R(Z) (10 point height of irregularities) and S (mean spacing of local peaks) of the patterns increased with increasing film thickness depending on the substrate withdrawal speed for dip-coating, the viscosity of the coating solutions, and the distance from the top edge of films. The shape of patterns changed from linear striations to cell-like patterns with increasing viscosity of the coating solutions. Although the heat treatment at 600 degrees C reduced the height (R(Z)) of stripes and cells without the change in spacing (S), the visibility of patterns was enhanced by the increase in refractive index due to the crystallization of films.
Uchiyama
Hiroaki
H
Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35 Yamate-cho, Suita 564-8680, Japan. h_uchi@kansai-u.ac.jp
Namba
Wataru
W
Kozuka
Hiromitsu
H