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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 Al 2 O 3 -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 Al 2 O 3 layer, the free-standing mesoporous carbon-silica 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 threedimensional (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 À1 , which is $4 times larger than that of its parental carbon-silica composite thin film.

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