A facile method to synthesize magnetic polymer nanospheres with multifunctional groups

Magnetic poly(styrene methyl methacrylate)/Fe3O4 nanospheres with ester groups were prepared by a modified one-step mini-emulsion polymerization in the presence of Fe3O4 ferrofluids. The effects of monomer dose, surfactant content, ferrofluid concentration and initiator content on the particle characteristics such as the size, morphology and magnetic properties were investigated by Fourier-transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis and vibrating sample magnetometer. The results indicated that magnetic nanospheres were superparamagnetic with high saturation magnetization of 51.0 emu/g and corresponding magnetite content of 61.5 wt%. Subsequently, magnetic nanospheres with carboxyl and amino groups were also obtained by hydrolysis and ammonolysis reaction. These magnetic nanospheres with multifunctional groups have biomedical applications.

Research highlights
► Facile way of synthesis of ester-functionalized superparamagnetic nanospheres.
► Wide scope of synthesis for other kinds of functional magnetic polymer nanospheres.
► The modification bilayer is the key factor controlling the encapsulation of products.
► Potential application of biomedical field.