Facetted hollow silica vesicles made by templating catanionic surfactant vesicles

Large facetted hollow silica vesicles were synthesized by directed growth of silica on equilibrium icosahedrally facetted catanionic vesicles, made from cetyltrimethylammonium hydroxide/myristic acid surfactant bilayers. Three critical parameters were identified: (i) the surface charge of the vesicles; (ii) the rate of silica deposition by tetraethoxysilane (TEOS) hydrolysis and (iii) the rate of concomitant ethanol production. All three factors are pH-dependent. Thus, depending on the reaction pH and TEOS concentration, the silica vesicles have been shown to be either facetted, rounded or damaged, in a process controlled by the template.