Facile preparation of bridged silsesquioxane microspheres with interconnected multi-cavities and open holes

Creating hollow structures in microspheres is attracting increasing interest because of the notable large capacity, high porosity, low density and extended surface area of the hollow microspheres prepared. Herein, facile preparation of bridged silsesquioxane (BSQ) microspheres with interconnected multi-cavities and open-hole structures is presented. The well-developed multi-cavities are derived from the configuration of the water-in-oil-in-water emulsion of the precursor. The condensation of the precursor in the emulsion results in the transition of the liquid precursor to solid BSQ resin, which preserves the emulsion structure and induces the formation of voids. The resultant hollow BSQ microspheres show advantages in controllable cargo delivery.