A novel approach to preparing polystyrene/Fe3O4 multihollow microspheres with porous walls

摘要

A novel approach is presented here to prepare polystyrene/Fe3O4 multihollow microspheres with porous walls. Water-in-oil-in water (W/O/W) double emulsion was developed in mini-emulsion system with the help of amphipathic Fe3O4 nanoparticles dispersed in oil phase. A gamma-ray irradiation from Co-60 source initiated the radical polymerization and controlled the reaction degree. Most of polymerization took place in mini-droplets of monomer developed during mini-emulsification process. Therefore, every mini-droplet of monomer with water inside can act like soft template, and polymerization helps to solidify such soft template and successfully reserve and transfer the morphology of these water-in-oil mini-droplets to solid microspheres. Multihollow structure was developed after drying since water inside of microspheres evaporated. Superparamagnetic property was also confirmed by VSM characterization on nanocomposites. Finally, the mechanism of forming such structure was preliminarily elucidated.