Synthesis of Large-Pore Mesostructured Micelle-Templated Silicas as Discrete Spheres

Abstract

The synthesis of large-pore micelle-templated silica (MTS) materials as discrete spheres by pseudomorphic synthesis solves the double challenge: enlarging the pore size of MTS beyond the diameter of the micelles and controlling the morphology and the size of the particles. The pseudomorphic transformation of silica beads of the desired size into MTS is one of the more suitable routes to control both nanometric and micrometric scales of MTS synthesis. The most employed method to enlarge pore diameter of MTS synthesized from alkyltrimethylammonium surfactants is to use 1,3,5-trimethylbenzene (TMB) as a swelling agent in the micelles. Unfortunately this method leads to particle aggregation. By means of the pseudomorphic route combining an original set of chemical compositions (C18TAB/decane/TMB/NaI), under mild conditions (low temperature, without autoclaving), we successfully synthesized nonaggregated MTS beads of 10 μm with pore diameter ranging from 7 to 9 nm, 900 m2/g specific surface area, and 1.5 mL/g...