Langmuir, Vol.26, No.13, 11479-11484, 2010
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 Mania films prepared titanium tetraisopropoxide (Ti(OC3H7i)(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 front 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.