Raspberry-like silica hollow spheres: Hierarchical structures by dual latex-surfactant templating route

Raspberry-like hollow SiO2 spheres were synthesized successfully through a dual latex-surfactant templating route. In this approach, cationic cetyltrimethylammonium (CTA(+)) micelles and microscale polystyrene (PS) latex were employed as structure-directing templates for constructing the inorganic hollow SiO2 spheres with hierarchical structures. The final product has been analyzed scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), single-angle X-ray diffraction (SAXRD), Brunauer-Emmett-Teller (BET) measurements, and Hg porosimetry measurements. The as-obtained hollow SiO2 spheres present a novel raspberry-like protruding surface morphology and possess hierarchical porous shells. Moreover, the factors that could impact the surface morphology and hierarchical porous structure are discussed, and the corresponding mechanism was proposed accordingly. This dual templating route is expected to be an effective means to pattern multiscale structures in the shell of the SiO2 microspheres; hence their potential applications could be greatly broadened.