Abstract
Colloidal silica spheres with controllable large through-holes and mesopores on the shell were synthesized by using polystyrene (PS) spheres as a hard template and cationic surfactant hexadecyl trimethylammonium bromide (CTAB) as a soft template. Through modulating the synthetic conditions, including the volume ratio of ethanol (EtOH)/water, the amount of ammonia hydroxide, and the dosage of CTAB, SiO
spheres can transform among hollow structure, through-hole structure, and no large pore structure. The investigation suggests that the hydrolysis rate of the silica source and the interaction strength between the PS sphere template and SiO
may determine the large pore structure of the final product. The moderate hydrolysis rate of tetraethyl orthosilicate (TEOS) and strong interaction between the PS sphere template and SiO
is conductive to the formation of large through-holes in SiO
spheres. To further investigate the pore structure of through-holes of SiO
spheres, the lysozyme (Lz) was selected as a model molecule for adsorption experiments. The Lz adsorption experiments show that SiO
spheres with through-hole structure exhibit a much faster adsorption rate than SiO
spheres with hollow structure and higher adsorption capacity than SiO
with no large pore structure. Such a behavior could find interesting applications in the fields that require a fast-loading characteristic.