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

Abstract

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.

Bringing Porous Organic and Carbon‐Based Materials toward Thin‐Film Applications

“…Mesopore sizes and mesostructures can be controlled by the template or by the composition of the template/carbon precursor mixture rendering soft‐templating a highly versatile method for synthesis of carbon thin films with a wide range of properties. Furthermore, the same group has shown that ordered mesoporous silica/carbon composite films can be synthesized by spin coating of a mixture of triblock copolymer Pluronic F127 (surfactant), resin (carbon precursor) and tetraethoxylsilane (silica precursor) on Al 2 O 3 ‐coated Si substrates (Figure B,C) . After carbonization and removal of the substrate as well as the silica part of the composite (acting as secondary hard template), free‐standing carbon films with significantly enhanced specific surface areas exceeding 2000 m 2 g −1 are obtained.…”

“…The inset in (e) shows structural models of the mesochannel orientation. C) Synthesis process for free‐standing mesoporous carbon–silica composite thin films, silica films, and carbon films by using a coating‐etching approach (B,C) reproduced with permission . Copyright 2013, the Royal Society of Chemistry.…”

A dual templating route to three-dimensionally ordered mesoporous carbon nanonetworks: tuning the mesopore type for electrochemical performance optimization

“…[1][2][3][4] Although the microporous carbons hold very high surface areas and pore volumes, their pore structures are uncontrollable and the pores are mainly contributed by micropores (< 2 nm), which are not favorable for quick electrolyte ion diffusion. 3,[8][9][10] In this regard, numerous techniques were developed to fabricate mesoporous carbons with diverse structures (films, 11-14 spheres [15][16][17] or free fibers 2,[18][19][20][21][22], including nanocasting, 14,16 soft-templating methods, 10,15,17,23,24 and so on. 3,[8][9][10] In this regard, numerous techniques were developed to fabricate mesoporous carbons with diverse structures (films, 11-14 spheres [15][16][17] or free fibers 2,[18][19][20][21][22], including nanocasting, 14,16 soft-templating methods, 10,15,17,23,24 and so on.…”

Addition of BaTiO₃ and carbon nanoparticles to silica aerogel and its dielectric properties

“…Recently, enhancement in permittivity below the percolation threshold and/ or a drastic increase in permittivity at the percolation threshold were observed in polymeric composites filled with conductive particles, such as metal or carbon, 20) 30) and aerogel composites. Si et al 31) and Hübert et al 32) reported the preparation and the electrical conductivity of carbon-silica porous nanocomposites. However, none of these previous studies reported dielectric properties.…”