Tunable assembly of organosilica hollow nanospheres

Hollow nanospheres with a particle size of less than 25 nm have been successfully fabricated using an ethylene-, phenylene-, and 1,4- diethylphenylene-bridging silane precursor with F127 as a soft template under an acidic medium. As the size and flexibility of the bridging organic group increases, it is more and more difficult for the formation of hollow nanospheres. The organic additive, 1,3,5-trimethylbenzene, could finely tune the particle size of the nanosphere from 12 to 25 nm. It was found that silane precursors with hydrophobicity and slow hydrolysis rate favor the formation of hollow nanospheres and hydrophilic silane precursors such as tetramethoxysilane induce the formation of mesostructured bulk materials. Under the current synthesis conditions, carefully tuning the interaction between templates and silica species, organosilica hollow nanospheres with controlled composition can be successfully obtained.