Magnetorheology of synthesized core-shell structured nanoparticle

Nanosized magnetic composite particles with polystyrene-acetoacetoxyethyl methacrylate (PS-AAEM) core and magnetite shell were prepared by controlled precipitation of inorganic precursors onto the core particles. This composite was adopted as a dispersed phase of magnetorheological (MR) fluids. Flow properties of shear stress and shear viscosity of the MR fluids were analyzed via a rotational rheometer equipped with a magnetic field supplier in parallel plate geometry, and it was found that this magnetic-composite-particle-based MR fluid exhibited typical MR characteristics, by showing not only a Bingham fluid behavior with a yield stress but also the increase of shear stress as a function of an applied magnetic field strength.