Preparation of Fe₃O₄/Polymethyl Methacrylate Composite Particles from Monolayer Oleic Acid-Modified Fe₃O₄

Mono disperse magnetic nanocomposite particles with high saturation magnetization have wide applications in biomedical fields. In this article, we have studied the structure of Fe₃O₄ nanoparticles with polymethyl methacrylate shell. First of all Fe₃O₄ nanoparticles were synthesized by co-precipitation method and then they were modified by oleic acid in order to put the poly methyl methacrylate layer via mini emulsion method. The surface properties of OA modified magnetite nanoparticles have great effects on preparation of composite particles. The monolayer OA modified Fe₃O₄ nanoparticles are more hydrophobic than the multilayer coated ones and by multilayer OA coated Fe₃O₄, there was a large amount of free poly methyl methacrylates in the solution of product. After coating, the monolayer nanocomposite particles formed monodisperse nanoparticles as it was demonstrated by DLS tests. The PMMA/Fe₃O₄ nanoparticles have spherical core shell structure with a proper size distribution. The VSM tests have showed that the Fe₃O₄/PMMA nanoparticles have high magnetic power. High saturation magnetization demonstrates the super paramagnetic property.