Vertically oriented hexagonal mesoporous zirconia thin films by block copolymer templating

We report the synthesis of vertically oriented, long-range ordered hexagonal mesoporous zirconia thin films. The orientation of hexagonally ordered cylindrical mesopores in thin films was effectively controlled by taking advantage of the temperature dependent hydrophobicity of the templating block copolymer PEO-PPO-EO. Vertical orientation was obtained when temperature was 30 degrees C or above throughout the process. Dehydration and enhanced chemical incompatibility between the PEO and PPO blocks at slightly elevated temperatures are proposed to play a key role in the vertical orientation of the mesopores. The temperature changes act on the entire film rather than just at the interfaces and the process can be applied to any mesoporous inorganic film.