Predictive design of ordered mesoporous silica with well-defined, ultra-large mesopores

Abstract

The influence of confinement in the nanometer scale on diffusion, adsorption, phase transition and catalytic conversion has recently gained increasing scientific attention. To study and ultimately understand its influence, mesoporous materials with narrow pore size distributions and a large range of different pore diameters are key. A simple method is presented to prepare ordered mesoporous silica materials with rationally addressable pore diameters between 4.5 and 21.5 nm, by using tailor-made block copolymers composed of poly(propylene oxide) (PPO) and poly(ethylene oxide) (PEO) with the generic structure PPO_n/2–PEO_m–PPO_n/2. A linear correlation between the number of propylene oxide units and the achieved pore diameter allows for a predictive synthesis, while the applied true liquid crystal templating process guarantees exceptionally narrow pore size distributions, even for ultra-large mesopores.