Ultra-large-pore mesoporous carbons templated from polyethylene oxide-b-polystyrene diblock copolymer by adding polystyrene homopolymer as a pore expander

A pore swelling approach was developed for the synthesis of ultralarge mesoporous carbons by using diblock copolymer PEO₁₂₅-b-PS ₂₃₀ as a template, homopolystyrene (h-PS₄₉) as a pore expander, resol as a carbon source, and THF as a solvent through solvent evaporation induced self-assembly (EISA). Smallangle X-ray scattering (SAXS) and transmission electron microscopy (TEM) characterizations show that when h-PS₉₄ amount is lower than 20 wt% relative to PEO ₁₂₅-b-PS₂₃₀, highly ordered face-center cubic (fee) mesoporous carbon structure (space group Fm3̄m) with ultralarge cell parameter of 46.4-58.0 nm can be obtained. Nitrogen sorption measurements reveal that the obtained LP-FDU-18s possess high surface area of about 1210 m ²/g and large pore volume of 1.10 cm³/g. Because of adding pore swelling agent h-PS₄₉, the mesostructural shrinkage is restrained, the pore wall thickness becomes very thin (3.6 nm). With the increase of h-PS₄₉ addition amount from 0 to 20 wt%, the pore size can be continuously tuned in the range of 22.9-37.4 nm. Excess h-PS₄₉ addition can lead to foamlike disordered porous carbons with multimodal pore size distribution (40-90 nm). A continuous solubilizing process is proposed to explain the expansion of pore size and cell parameter. This approach could be extended to the synthesis of other large-pore mesoporous materials with different frameworks such as silica, silica-carbon composite, and metal oxides.