Core/shell structured silica spheres with controllable thickness of mesoporous shell and its adsorption, drug storage and release properties

In this study, a simple method to coat mesoporous silica layer onto solid silica spheres in a controlled manner via a two-step procedure is reported. Core/shell structured SiO2@m-SiO2 spheres with different shell thickness have been obtained by the application of the optimized hexadecyl trimethyl ammonium bromide/tetraethylorthosilicate (CTAB/TEOS) ratio. The specific surface areas of the obtained samples increase with the shell thickness increase from 25 nm to 90 nm. The adsorption ability, storage and release properties related to mesoporous shell thickness and pore sizes were explicitly investigated with Rhodamine B (RhB) as the model molecules.