Superparamagnetic nanocomposite particles synthesized using the mini-emulsion technique

Nanocomposite particles containing high concentrations of superparamagnetic γ-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 ∼25 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.