Novel Polymeric Organosilica Precursor and Emulsion Stabilizer: Toward Highly Elastic Hollow Organosilica Nanospheres

The fabrication of hollow organosilica nanoparticles with high elasticity is greatly desirable but still challenging. Herein, we present a new and simple strategy to prepare such nanoparticles by using hyperbranched polyvinylpolytrimethoxysilane (PVPMS) via a soap-free oil in water (O/W) emulsion system. PVPMS was synthesized through the radical polymerization of vinyltrimethoxysilane (VMS) followed by the acid-catalyzed hydrolytic polycondensation of trimethoxysilyl groups, which works not only as an organosilica precursor but also as a sole emulsion stabilizer due to its hydrolysis-induced amphiphilicity at the oil/water interface. When styrene was used as the oil phase and initiated to polymerize, hybrid polystyrene (PS) core-organosilica shell (PS@organosilica) nanoparticles were obtained by controlling the reaction conditions. Furthermore, highly elastic hollow organosilica nanospheres with low Young's modulus (similar to 220 MPa) were yielded through solvent etching of the core. This study expands the scope of organosilica precursor from small molecule organosilane to polymeric macromolecule and provides useful guidance for application in other polyorganosilsesquioxane related hybrid organosilica particles and functional hollow nanoparticles.