Acta Phys. -Chim. Sin. ›› 2010, Vol. 26 ›› Issue (11): 3120-3126.doi: 10.3866/PKU.WHXB20101027


Magnetite Sub-Microspheres with Controlled Diameter and Magnetic Properties Synthesized by the Citrate-Assisted Polyol Process

YAN Gong-Qin, WANG Wei, SUN Zhi-Gang, GUAN Jian-Guo   

  1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, P. R. China
  • Received:2010-05-07 Revised:2010-06-17 Published:2010-10-29
  • Contact: GUAN Jian-Guo
  • Supported by:

    The project was supported by the National High-Technology Research and Development Programof China (2006AA03A209) and Young Teachers fromFok Ying Tung Education Foundation, China (101049).


Monodispersed superparamagnetic magnetite (Fe3O4) sub-microspheres with controlled grain sizes and diameters were obtained by a facile polyol solvothermal method using sodium citrate as an additive. The results show that citric ions, which strongly coordinate with iron atoms on the surface of magnetite, can be effectively adsorbed onto the surface of Fe3O4 nanoparticles. Therefore, the growth of the initially formed Fe3O4 nanoparticles is restrained and the electrostatic repulsive force changes. Consequently, both the diameter and the magnetic properties of the resultant Fe3O4 sub-microspheres can be easily tuned over a relative large range. Simply changing the concentration of citric or ferric ions can change both the diameter of the Fe3O4 nanoparticles which construct the resultant sub-microspheres as building blocks and that of the resultant sub-microspheres in a range of 220 -550 nm, resulting in monodispersed superparamagnetic magnetite sub-microspheres.


Key words: Superparamagnetism, Monodispersed sub-microspheres, Magnetite, Diameter control, Citrate


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