Free-standing highly ordered mesoporous carbon-silica composite thin films

摘要

Free-standing mesoporous carbon-silica composite films with different silica contents are successfully prepared with a crack-free morphology, square centimeter size, and a highly ordered mesostructure. The films are first synthesized on AI2O3-coated Si substrates by spin-coating of a tri-constituent solution, in which triblock copolymer Pluronic F127, resin and tetraethoxylsilane (TEOS) are used as the template, carbon and silica precursors, respectively. After the organic-inorganic assembly, calcination, and etching of the intermediate Al2O3 layer, the free-standing mesoporous carbon-siiica composite films are obtained. The mechanical property, water wettability and electrical conductivity are well adjusted with different carbon-silica ratios. Furthermore, the free-standing carbon or silica films are also prepared by hydrofluoric acid etching of the carbon-silica composite film or calcination in air, owing to the three-dimensional (3D) interpenetrated frameworks of their parental carbon-silica composite films. The surface area of the obtained free-standing carbon film is extremely high up to ~2030 m~2 g~(-1), which is ~4 times larger than that of its parental carbon-silica composite thin film.