The syntheses of transparent thin layers and spherical particles of nanoporous silicas

Thin layers of silica-surfactant hybrids with the thickness of several tens of nm formed on flat substrate from basic aqueous methanol solution containing tetraethoxysilane, behenyltrimethylammonium chloride, and ammonia. From the same solution, micrometer sized spherical particles of silica-surfactant hybrids were obtained. Both film and spherical particles were transformed to nanoporous silicas by calcination in air. The synthetic variables have been examined to find following dominant experimental parameters; the pore size of nanoporous silica spherical particles can be controlled by the synthetic temperature and the thickness of the films was varied by the amount of base.