Synthesis and characterization of surfactant and silica-coated cobalt ferrite nanoparticles

In this paper we report the synthesis and the characterization of ferrofluids constituted by cobalt-ferrite nanoparticles obtained from two different synthetic pathways: microemulsions and supersaturated solutions. Microemulsion technology leads to the formation of surfactant-coated magnetic nanoparticles, while dispersions of nanoparticles stabilized by their surface charges has been obtained by precipitating cobalt-ferrite from a supersaturated solution. The synthesis of a shell of silica on top of these nanoparticles is also reported. Surfactant coated nanoparticles have been characterized by means of UV–Vis absorption spectroscopy and trasmission electron microscopy (TEM), while nanoparticles obtained by supersaturated solutions have been studied by means of small-angle X-ray scattering (SAXS).