Static yield stress of a magnetorheological fluid containing pickering emulsion polymerized Fe3O4/polystyrene composite particles

Magnetorheological (MR) fluids are a type of smart material with rheological properties that may be controlled through mesostructural transformations. MR fluids form solid-like fibril structures along the magnetic field direction upon application of a magnetic field due to magneto-polarization of particles suspended in the inert medium. A reverse structural transition occurs upon removal of the applied field. The structural changes occur very quickly, on the order of milliseconds. Recent applications have increased the demand for better performing MR materials with good long-term stability. A variety of industrial MR materials have been developed and tested in experimental and theoretical studies. This article briefly describes our recent progress in the search for advanced MR fluid materials and novel approaches to analyzing the MR flow behavior. To distinguish between the static yield stress and the dynamic yield stress and to describe the flow behavior under a broad range of shear rates, we applied Seo-Seo model. Several routes to improving the stability and efficiency of the MR fluids are summarized.