Synthesis of n-Hexadecylphosphonic Acid-Coated Monodisperse Fe3O4 Superparamagnetic Nanoparticles

Monodisperse Fe3O4 Superparamagnetic Nanoparticles Were Synthesized in N-Hexadecylphosphonic Acid/ Cyclohexane/ Water/ Ethanol Microemulsion under Solvothermal Conditions at 100°C. the Crystal Structure and Particle Size of Synthesized Fe3O4 Were Observed by X-Ray Diffraction (XRD) as Well as Transmission Electron Microscopy (TEM). the Results Show that the Nanoparticles Have a Cubic Crystal System and a Average Particle Size of about 10nm. each Nanoparticle Has a Single Crystal Structure. the Surface Chemistry of Synthesized Fe3O4 Nanoparticles Was Characterized by Fourier Transform Infrared Spectroscopy (FTIR), Indicating that the Nanoparticles Were Covered by a Layer of N-Hexadecylphosphonic Acid, which Made the Nanoparticles Totally Lipophilic. Magnetic Properties of the Nanoparticles Were Investigated by Using Vibrating Sample Magnetometer (VSM). the Result Reveals that the Saturation Magnetization (Ms) of the Nanoparticles Is Higher than 40 Emu/G and the Coercive Force Is near to 0. the Monodisperse Fe3O4 Nanoparticles Have Superparamagnetic Property and May Find Potential Applications in many Fields, such as Ferrofluids, Drug Loading and Release, Selective Biomolecular Separation and MRI.