The Study Of Surfactants On Giant Electrorheological Fluid

Electrorheological(ER)fluids are a kind of smart colloid consisting of nanoparticles with a high dielectric constant suspended in an insulating base fluid.The rheological properties(yield stress,viscosity,etc.)of ER fluid can be controlled reversibly and continuously by an external electric field.The transformation in the rheological characteristics is fast and reversible.However,the development of ER fluids is restricted owing to the poor performance of Electrorheolohical Effect.It was only in 2003,Prof.Wen reported Giant Electrorheological(GER)fluids consisting of urea-coated nano-sized barium titanyl oxalate(BTRU)particles suspended in silicone oil.Yield stress of GER fluids can exceed 130 k Pa and breaks the limit of conventional ER fluids.Due to the invention of GER fluids,the ER actuators have a considerable development,such as clutches,dampers,valves,etc.However,balanced performance of GER fluids are necessary in industrial application which includes current density,GER effect,dispersion,sedimentation and viscosity.In this paper,it is the first time for us to improve the dispersion of GER fluids by adding nonionic surfactant(silicone polyether)and find that silicone polyether could reduce particle agglomeration in GER fluids and the sedimentation of GER fluids.Moreover,a suitable content of silicone polyether could decrease the current density of GER fluids and energy consumption which reduces the risk of breakdown.However,the added silicone polyether molecules lead to a recession in the yield stress.Ultimately,an optimal solution was obtained by making tradeoffs among the dispersion,current density,viscosity,anti-sedimentation and ER effect.Besides,a GER Fluid Pilot Plant is built which can produce a large amount of BTRU particles.The impact of drying hours,ball-milling hours and temperature on the performance of GER fluids are studied in detail.