Preparation And Characterization Of Fe₃O₄ Nanoparticles Coated With Organic Compounds

In this paper, Fe3O4 nanoparticles modified by one or two kinds of surfactants were prepared by wet chemical methods.Moreover,using these Fe3O4 nanoparticles, we successfully prepared magnetic polymer microspheres(MPM).The detailed contents are given as following:1)Using ferric trichloride,ferrous sulfate and sodium hydroxide as main sources,sodium oleate and PEG respectively as surfactants,we prepared the well-dispersed Fe3O4 nanoparticles via a coprecipitation method.From the characterizations of the nanoparticles by XRD,TEM,FT-IR and VSM,it shows that:the dispersibility of the modified Fe3O4 particles was improved visibly;no effects on the crystalline structure can be confirmed before and after using the surfactants;the modified Fe3O4 nanoparticles were of superparemagnetic behavior.2) Both sodium oleate/PVP and sodium oleate/PEG were used as multiplicate surfactants to prepared Fe3O4 nanoparticles by a coprecipitation method.The studies of XRD,TEM,FT-IR and VSM on the as-prepared nanoparticles reveal that:the dispersibility of the as-prepared Fe3O4 nanoparticles was improved obviously compared with that of the Fe3O4 particles modified with one surfactant;no effects on the crystalline structure of Fe3O4 nanoparticles before and after the modifications;the as-prepared Fe3O4 nanoparticles exhibited superparemagnetic performance.3)Using PEG/Fe3O4 nanoparticles as cores,BPO as an initiator, we successfully synthesized the magnetic polystyrene microspheres(MPM)inâ–¡thanol-water solution via a dispersion-polymerization method.The results of characterization of the as-synthesized MPM by XRD,TEM,FT-IR,TG and VSM showed that the MPM particles with an average particle size of 80 nm, saturation magnetization of 20.7 emu/g exhibited distinct superparamagnetic characteristics at room temperature.