Morphology control of microporous silica particles obtained by gradual injection of reactants

Industrial-scale synthesis of fine-tuned monodisperse microporous silica is a central concern on fillers and optical applications. We recently reported that the efficient synthesis of monodisperse microporous silica particles can be achieved by the gradual injection of reactants. In the present study, we investigated the influence of the injection kinetics, the template, and catalyst contents on the morphology of the resulting silica particles. Their specific surface area (SSA) could be tuned from 100 to 500 m²/g by the amount of templating molecule, n-dodecylamine, without changing the particle size and dispersibility. The most important parameters for controlling the particle size were found to be the amounts of catalyst. The resultant microporous and monodisperse silica particles exhibit diameter ranging from 20 to 200 nm and SSA from 50 to 1000 m²/g. These results show that the gradual injection of the reactants in a controlled manner is effective to the industrial-scale synthesis of the silica nanoparticles with expected morphologies.