Superparamagnetic nanocomposite particles synthesized using the mini-emulsion technique

Nanocomposite particles containing high concentrations of superparamagnetic gamma-Fe2O3 nanoparticles dispersed in PMMA were prepared using the mini-emulsion polymerization. A suspension of coated iron-oxide nanoparticles in the MMA was added to an aqueous solution of SDS and then ultrasonified to promote the formation of the mini-emulsion. By changing the content of SDS, nanocomposite particles with an average diameter from similar to 25 to similar to 50 nm were obtained. TEM showed that the core of the prepared nanocomposite particles was composed of iron-oxide nanoparticles homogeneously distributed within a polymer matrix and a thin polymer shell. The content of magnetic nanoparticles dispersed in the polymer was as high as 39 wt.%, resulting in a high saturation magnetization of 27 emu/g. (C) 2010 Elsevier B.V. All rights reserved.