Core–shell-structured Fe3O4 nanocomposite particles for high-performance/stable magnetorheological fluids: preparation and characteristics

Magnetorheological (MR) fluids are a type of smart material of which rheological properties can be controlled through mesostructural transformations. They are generally magnetically responsive particle suspensions, which consist of magnetizable particles dispersed in a non-magnetic liquid medium. Ferromagnetic or ferrimagnetic particles with a micrometer size are suitable for MR fluid suspensions, since they can be polarized by the external magnetic field to form chain-like aggregates (mesostructures) that have a strong yield strength and can induce a high shear viscosity. Fe3O4 particles are good candidates for high-performance MR materials due to their low density and high magnetic properties as well as their excellent surface activities. To improve the stability of the MR suspension, many studies on the synthesis of Fe3O4-containing nanocomposites have been carried out recently. This review deals with the latest advances in the fabrication of Fe3O4 nanocomposite particles with a core–shell structure as well as their critical characteristics and advantages to be used in MR suspensions. We focused on the synthesis strategy of various Fe3O4 nanoparticles with a core–shell structure as well as their performance in the magnetic fields.