Compressible Magnetorheological Fluids Based on Composite Polyurethane Microspheres

A novel CMRF is synthesized from modified silicone oil, containing composite polyurethane microsphere additives, and surface-coated iron particles. The CMRF is designed to act as a liquid spring with controllable damping properties in a damper system. The fluid compressibility is characterized by force/displacement measurements. The addition of composite polyurethane-microspheres increases the strength and compressibility of the fluid. It also decreases the concentration of iron particles needed in order to achieve the same yield stress as commercially available MRF. Surface coating surface of the iron particles with poly(2,3,4,5,6-pentafluorostyrene) via RAFT provides dispersion stability.