Preparation of spherical caged superparamagnetic nanocomposites with completed inorganic shell via a modified miniemulsion technology
Abstract A one-pot facile method is developed to synthesize spherical caged polystyrene/Fe3O4@SiO2 nanocomposites (SCNs) microspheres with intact inorganic shells in a high yield via a combining process of miniemulsion polymerization and sol–gel reaction. It is revealed that St to TEOS ratio, the controlled hydrolysis and condensation rate of TEOS both play important roles in the structure formation. Control experiments are performed to understand the possible mechanism. With iron oxide nanoparticles as inorganic seeds, this one-pot synthetic method shows apparent advantage over multi-step layer-by-layer coating and selective etching regarding the simpleness and efficiency. Regular hollow magnetic mesoporous silica composites could easily be prepared using the caged magnetic microspheres as the template. The novel and facile method for preparing the magnetic composites with intrinsic space and intact shell could promote the development of drug carrier or photocatalysis system.