Core/Shell Polystyrene/Magnetite Hybrid Nanoparticles Fabricated by Pickering Emulsion Polymerization and Their Magnetorheological Response

Abstract

Abstract Soft‐magnetic polystyrene (PS)/Fe 3 O 4 core/shell composite nanoparticles are fabricated by surfactant‐free Pickering emulsion polymerization using Fe 3 O 4 nanoparticles as a solid stabilizer. The morphology of the synthesized PS/Fe 3 O 4 particles consisting of a PS surface coated with Fe 3 O 4 nanoparticles is examined by scanning electron microscopy and transmission electron microscopy. The thermal properties of Fe 3 O 4 and PS/Fe 3 O 4 are examined by thermogravimetric analysis, while the chemical bonding and composition of the nanocomposite are characterized by Fourier transform infrared spectroscopy and X‐ray diffraction. The magnetorheological (MR) properties of the PS/Fe 3 O 4 composite nanoparticles dispersed in silicone oil are analyzed using a rotational rheometer under an external magnetic field. The PS/Fe 3 O 4 ‐based MR fluids exhibit typical MR properties and a lower density compared to Fe 3 O 4 nanoparticles, indicating the improved dispersion stability of the MR fluid compared to that of the Fe 3 O 4 nanoparticle‐based MR fluid.