Magnetite CoFe2O4 nanoparticles were modified by a new series of. fluorine-containing polymeric dispersants. The Fourier transform infrared spectroscopy ( FTIR) and element analysis showed that the polymer chains have been successfully adsorbed onto the surfaces of the CoFe2O4 nanoparticles. The influence of the content of. fluoroalkyl groups on the surface tension and the dispersing properties were also investigated and the results showed that the modified CoFe2O4 nanoparticles exhibit excellent surface active properties and the nanoparticles can be dispersed very well in the aqueous phase. Zeta potential and the average diameter of the nanoparticles can reach to -68 mV and 42 nm with the increasing of the content of. fluoroalkyl groups of the polymeric dispersant, respectively. (C) 2008 Elsevier B. V. All rights reserved.