The preparation of TiO2/SiO2 composite hollow spheres with hydrophobic inner surface and their application in controlled release

The TiO2/SiO2 composite hollow spheres (CHSs) with hydrophobic inner surface have been successfully synthesized by using carboxyl-functionalized polystyrene spheres as templates. The inner titania shell was selectively modified with stearic acid (SA). The morphologies, structures, drug loading amounts and release rates were characterized and investigated by SEM, TEM, XRD, N2 adsorption–desorption isotherms, FT-IR, TG and HPLC analysis. Due to the hydrophobic interaction, the modified inner surface slowdown the release of the hydrophobic drug into the aqueous environment. The SA modified CHSs displayed higher drug loading amounts as well as lower release rates than that of unmodified spheres. The studies demonstrate that composite hollow spheres are promising for the multifunctional controlled release.