Magnetic filed-assisted synthesis of Fe3O4/chitosan nanocomposites by co-precipitation method

摘要

Chitosan coated magnetite nanocomposites (Fe3O4/chitosan) were synthesizedunder external magnetic fields by the method of co-precipitation. The obtainedFe_3O_4/chitosan were characterized by X-ray diffractometer (XRD), Fourier transform infraredanalysis（FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy(SEM) analysis. XRD and FT-IR results showed that the Fe3O4/chitosan nanocompositeswere validated as the binding of Fe3O4 and chitosan. The images of TEM also revealed themagnetite crystals were encapsulated by chitosan. In our study, Fe3O4/chitosannanocomposites with different structures could be synthesized by changing the intensity ofthe external magnetic fields in the reaction process. SEM images showed that Fe3O4/chitosan nanocomposites were spherical particles with an average size of about 30nm anddistributed randomly without magnetic field placed. However, the morphology ofFe3O4/chitosan nanocomposites was obviously changed when there was an externalmagnetic field applied. Some particles assembled and presented chain-net cluster structuresin the present of a magnetic field at 0.25 T. In addition, Fe3O4/chitosan nanocompositesformed to rod cluster structures with the length diameter ratio rang of 5~10, when themagnetic field intensity reached 0.45 T. The effect of magnetic field on magnetic propertiesof Fe3O4/chitosan nanocomposites was also evaluated by the vibrating samplemagnetometer (VSM). It symptomatized that the nanostructures obtained from ourexperiments all had the characteristics of superparamagnetism with and without the externalmagnetic field.