Novel Processing for Mesoporous Silica Films with One‐Dimensional Through Channels Normal to the Substrate Surface

Mesoporous silica films with one‐dimensional through channels perpendicular to the substrate surface have been fabricated successfully by a novel process, which was a combination of eutectic decomposition of amorphous films and subsequent chemical etching. In the case of the Fe–Si–O system, amorphous precursor films annealed under oxidizing conditions were decomposed to a regular array of needlelike hematite (Fe 2 O 3 ) crystals with a diameter of ∼4 nm surrounded by an amorphous silica matrix. Then, hematite crystals were preferentially removed by chemical etching. The pore surface areas of the remaining mesoporous SiO 2 films were found to be more than 1000 m 2 /g by an isothermal N 2 gas adsorption and desorption measurement.