Abstract
Nearly monodisperse, well crystalline, superparamagnetic CoFe2O4 nanoparticles with diameter of 6 nm were synthesized in oleic acid-water-pentanol system at 180 _C. Hydrothermal procedure, as an efficient and environment friendly alternative to organic decomposition methods, was investigated by variation of reaction conditions, and the particle formation mechanism was finally proposed (i.e., hydrolysis of metal oleates in organic phase, with size of the particles (5-8 nm) controlled by polarity-driven precipitation into water phase).
As-prepared particles were hydrophobic due to coating by oleic acid. Further modification with dimercaptosuccinic acid led to water-dispersible particles with hydrodynamic diameter of 20 nm.
Prepared particles were investigated by TEM, XRD, ICP-AES, light scattering, SQUID magnetometry, and Mossbauer spectroscopy.