Large-pore ordered mesoporous carbons with tunable structures and pore sizes templated from poly(ethylene oxide)- b-poly(methyl methacrylate)

Abstract

Ordered mesoporous carbons (OMCs) with possible face-centered cubic (space group F m 3 ¯ m ) and 2-D hexagonal ( p6 mm) symmetries have been successfully synthesized by using lab-made poly(ethylene oxide)- block-poly(methyl methacrylate) diblock polymers (PEO- b-PMMA) with different PEO/PMMA ratios as a template. The synthesis process undergoes an evaporation induced self-assembly (EISA) at 100 °C by using low-molecular weight phenolic resol as a carbon source and tetrahydrofuran (THF) as the solvent. The atom transfer radical polymerization (ATRP) method was used to prepare the diblock copolymers with different molecular weight and compositions of PEO and PMMA segments by simply changing the PEO initiator and polymerization time. For the first time, we have obtained OMCs with hexagonal p6 mm symmetry and large pore size (8.6–12.1 nm) by using PEO- b-PMMA with long PMMA segment as the templates. Notably, the pore size of the ordered mesoporous carbons can be tuned in the range of 8.6–22.0 nm by slightly adjusting the hydrophobic PMMA length of the template or adding desired amount of PMMA homopolymer as a pore expander. Additionally, it is found that the pore wall thickness of OMCs with possible face-centered cubic symmetry can be adjusted from 8.1 to 10.4 nm by simply increasing the weight ratio of resol to the template ( R w).