Study On The Preparation Of Iron Oxide Nanocrystal/Nanoclusters And Its Properties

Magnetic nanoparticles, because of their unique magnetic, electrical, optical and otherproperties, as compared with their bulk materials, have attracted considerable attentions.Nanostructured magnetic particles have an extensively potential application, especially inbiomedicine such as magnetic resonance imaging (MRI), bioseparation, hyperthermia,targeted drug delivery. Magnetic nanoparticles, especially iron oxide magneticnanoparticles because of its biocompatible and biodegradable, non-toxic to humans, highsaturation magnetization and other excellent properties are widely used in biomedicine. Avariety of synthetic methods for iron oxide nanoparticles have been developed, such asco-precipitation, inverse microemulsion, hydrothermal method, microwave-assistedmethod, sol-gel method, solvothermal method. Recently, the focus of syntheticinteresting has been directed towards the creation of secondary structures of magneticiron oxide nanocrystal clusters, which consist of multiple single superfine magneticnanocrystals and assembled into submicrometer scale clusters. Fe3O4nanocrystal clustersnot only maintain the superparamagnetic characteristic of single superfine iron oxidenanocrystal, but also ensure the nanocrystal clusters has a strong enough magneticresponse under the effect of an external magnetic field. Fe3O4nanocrystal clusters haveimportant application prospects in the biomedical field. In this paper, major results havebeen researched as follow:(1) Monodispersed cubic iron oxide nanocrystals with the same phase structure andwith size uniformity were prepared by decomposition of homemade iron oleate in hightemperature organic solvent. The structure and magnetic properties of as-prepared ironoxide nanocrystals were studied. The effects of surfactant on the size and morphology ofas-prepared iron oxide nanocrystals were also discussed.(2) Superparamagnetic Fe3O4nanocrystals clusters were prepared by the solvothermalmethod, with FeCl3as raw materials, a variety of organic solvents as reaction medium.Particle size and morphology control can be attained by careful adjustment of the amountof FeCl3, the species and volume ratio of organic solvents, surfactant, reaction time and reaction temperature. X-ray powder diffraction (XRD), transmission electron microscopy(TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM)and fourier transform infrared (FT-IR) were used to characterize the structure,morphology and magnetic properties of the prepared products. A series of size-controledFe3O4nanocrystals clusters have been prepared. The size of Fe3O4nanocrystal clustershave been controlled from80nm to700nm.