Magnetic Iron Oxide Microspheres Prepared By Solvent-thermal Method And Silica-coated Study

Magnetic iron oxide is widely used because of its unique physical and chemical properties, as well as in magnetic separation, targeted drug delivery, catalysis, magnetic response of photonic crystal, magnetic self-assembly and other areas, has become a hot topic in recent years.In this work, we mainly focused on the preparation of Fe3O4microspheres with narrow size distributions and high magnetic saturation. The effect of reaction time, solvent, concentrations of sodium acetate, ferric chloride and water were systematically studied in order to synthesize monodispersed Fe3O4microspheres with controllable size and morphology. The monodispersed Fe3O4microspheres with average diameter ranges from100to600nm were successfully obtained by a solvothermal reduction method via a4h reaction. Besides, hollow structure can also be obtained by simply altering the water concentration in the reaction system.The morphology and structure of the products were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). And those test results confirmed the pureness and well crystallization of the nearly monodispersed products. Fourier Transform Infrared Spectrometer (FTIR) and vibration sample magnetometer (VSM) were also used to characterize the surface property and magnetic properties of Fe3O4microspheres separately.In addition, the Fe3O4@silica composite microspheres were prepared by a modified Stober method. By modifying the surface of Fe3O4microspheres with polyvinyl pyrrolidone, we successfully obtained the monodisperse Fe3O4@silica composite microspheres with uniform silica coating. Finally, the induced self-assembly behaviors of Fe3O4microspheres and Fe3O4@silica composite microspheres were also investigated.