Preparation of thermo-responsive hydrogel-coated magnetic nanoparticles

We propose and demonstrate a facile synthetic method for obtaining magnetic nanoparticle cores with a thermo-responsive polymeric hydrogel shell using the miniemulsion polymerization method. The magnetic nanoparticles approximately 9 nm in diameter were first prepared by a thermal decomposition method, and then, the magnetic nanoparticles were used as hydrophobes during the reaction, forming aggregated magnetic particles over-coated with a polymer layer. Transmission electron microscopy shows that as-prepared particles possess core–shell structures of 40–100 nm of aggregated magnetic-core nanospheres with an approximately 15 nm thick polymer shell over the iron oxide cores. The nanocomposites were also characterized by X-ray diffraction, vibration sample magnetometer and dynamic light scattering techniques.

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► Core–shell structure magnetic nanoparticle-NIPAAm particles were prepared.
► The magnetic nanoparticle-NIPAAm composites had a high saturation magnetization.
► They showed both magnetic and thermo-responsive characteristics.