Evaporation-Induced Alignment of Cylindrical Mesopores in TiO2 Thin Films

Hexagonally packed cylindrical mesopores that are vertically aligned at the surface of mesoporous TiO2 thin film are formed by self-assembly of the hydrolyzed titanium alkoxides in the presence of poly(styrene-b-ethylene oxide) building blocks. The mesoporous thin film exhibits a high degree of lateral ordering and thermal stability. Long-range lateral ordering and orientation of mesopores at the TiO2 film surface arise from a strong unfavorable interaction between the polystyrene and poly(ethylene oxide) building blocks, together with the cooperative assembling between the building blocks and inorganic species in association with the directionality of solvent evaporation.