Increasing the Porosity of Silica Particles by Reducing the Thickness of Nanochannel Walls and Producing an Additional System of Micropores

We have developed a technique for the preparation of submicron spherical micro- and mesoporous silica particles via basic hydrolysis of organosilanes in an ethanol-water-ammonia mixture in the presence of cylindrical alkyl amine micelles. The particles synthesized in the presence of diethoxy(3-glycidyloxypropyl)methylsilane have been shown to contain cylindrical SiO2 nanochannels with an inner diameter of 3 nm, characteristic of nanostructured M41S-type materials, but with a smaller wall thickness (0.5 instead of 0.7 nm). Owing to this, the specific surface area and volume of pores increased from 750 to 1200 m(2)/g and from 0.5 to 0.7 cm(3)/g, respectively. The addition of 3-(methacryloyloxy)propyltrimethoxysilane to the reaction mixture leads to further increase in these parameters (up to 1400 m(2)/g and 0.8 cm(3)/g) owing to micropore formation in the nanochannel walls.