Synthesis & Phase Transfer Of Monodisperse Fe₃O₄ Nanoparticles

High temperature precursor thermal decomposition is a newly developed method for the synthesis of the monodisperse magnetic nanoparticles. The particles synthesized by this method have good crystalline character, narrow size distribution. Size of the nanoparticles can be precisely controlled by adjusting the experiment parameter. But the study about another important factor for the particles physical and chemical properties—shape was very few. And the nanoparticles synthesized by this method are hydrophobic which limit the applications of these nanoparticles in the biomedical field. The monodispersed Fe3O4 nanoparticles were synthesized by the precursor thermal decomposition method with the ferric acetyl-acetonade as the precursor. The monodisperse cubic Fe3O4 nanoparticles were synthesized in one step reaction or two step seed-mediated growth methods by controlling the growth temperature and the amount of the diol or the surfactant. The size of the as-synthesized is 14.2 and 12.3 nm, respectively. The shape of the nanoparticles can be exchanged between sphere and cube. The properties of the surface modified ligands and the magnetic perperties of the particles were characterized by TEM, HRTEM, XRD, FTIR, HPPS, TGA and PPMS. The cubic particles are monocrystal which were terminated by six {100} planes. The iron atoms in the particle surface combined with oxygen atoms of the carboxyl of the oleic acid by covalent bond. We found the concentration of the nanoparticles playing as the key factor for the self-assembly process. With the increase of the concentration, the arrangement of the nanoparticles changed from disorder to ordered monolayer, then to ordered multilayer. The...