Abstract: Based on the cooperation of surfactants, metal precuesor and liquid environment, monodisperse nanoparticles of hexagonal Fe3O4 magnetite were prepared by 1,2-dodecanediol reduction of iron acetylacetonate[Fe(acac)3] in the presence of oleic acid and oleylamine. The effects of surfactants   reductant on the particles' size and morphology were examined. TEM results show that the use of oleic acid and oleylamine suppressed the growth of magnetite nanoparticles and made the particles size reduced from 24.2 nm to 7.6 nm; a variety of particles morphology arose and schistic hexagonal Fe3O4 nanoparticles were achieved. Magnetic properties show that the as-synthesized Fe3O4 nanoparticles possess features of high saturation magnetization Ms(88 A·m2/kg) and zero remanent magnetization Mr, facilitating their use as magnetic tags for biomedical applications.

Key words: Polyol reduction process, Hexagonal Fe3O4 nanoparticle, Oleic acid, Oleylamine, 1,2-Dodecanediol, Magnetic tag