Preparation and Reversible Phase Transfer of CoFe₂O₄ Nanoparticles

In this paper, we present a chemical co-precipitation approach in aqueous solution to prepare a highly crystalline monodispersed CoFe 2 O 4 magnetic nanoparticles coated with oleic acid. These products can be transferred into organic solvent by adjusting to pH 5 under the effect of HCl and re-transferred into water phase from organic phase completely under the effect of (CH 3 CH 2 ) 3 N by adjusting the added amount into the water phase. X-ray diffraction, energy-dispersive spectrometry, transmission electron microscopy, and UV−vis spectra were used to characterize these nanoparticles and their reversible phase transfer. The properties of the reversible phase transfer imply the novel CoFe 2 O 4 products have great potential applications in nanotechnology.