title: Development of high magnetization Fe3O4/polystyrene/silica nanospheres via combined miniemulsion/emulsion polymerization.
abstract: Monodispersed, hydrophilic, superparamagnetic magnetic nanospheres with a high fraction of magnetite were synthesized by combining modified miniemulsion/emulsion polymerization and sol-gel technique for the first time. The surface of the nanospheres was coated by a silica layer with controlled thickness. Transmission electron microscopy experimental results showed well-proportioned, equal-sized, magnetite/polystyrene (Fe3O4/PS) nanospheres with a thin silica shell. Based on the TGA data, the fraction of magnetite in the Fe3O4/PS nanospheres core was estimated to be 80 wt %. Magnetization measurements indicated that the superparamagnetic nature of the nanospheres had high saturation magnetization of 40 emu/g at 300 K. The procedures of the novel synthesis are described in detail. Also discussed are the mechanisms of the novel combined miniemulsion/emulsion polymerization processes.
authors.affiliation: National Key Laboratory of Nano/Micro Fabrication Technology, Research Institute for Micro/Nano Science and Technology, Shanghai Jiaotong University, Shanghai 200030, PR China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Longlan
authors.initials: L
authors.lastname: Cui
authors.forename: Naihu
authors.initials: N
authors.lastname: Tong
authors.forename: Hongchen
authors.initials: H
authors.lastname: Gu
mesh_terms: D001709:Biotechnology / Q000379:methods*; D004655:Emulsions; D005290:Ferric Compounds / Q000737:chemistry*; D008280:Magnetics; D049329:Nanostructures / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D004655:Emulsions; D005290:Ferric Compounds; D011108:Polymers; D011137:Polystyrenes; C000499:ferric oxide; D012822:Silicon Dioxide