Thermogelling magnetorheological fluids

Abstract

A novel approach is proposed for the formulation of kinetically stable magnetorheological (MR) fluids exhibiting an MR effect. Thermoresponsive carrier fluids are used which develop a sol–gel transition on increasing the temperature. Turbidity measurements, multiwave rheology and steady shear flow tests are carried out on model conventional MR fluids prepared by dispersion of carbonyl iron microparticles in triblock copolymer solutions of type PEOx–PPOy–PEOx with x = 100 and y = 65. Experiments demonstrate that the MR fluids remain stable against sedimentation in the gel phase and exhibit a very large (relative) MR effect (up to 1000%) in the sol phase.