Novel electrorheological materials with ternary blends containing polyethers and urethanes

Ternary ER blends composed of two different liquids and solid dispersoid were prepared by blending silicone oil, viscous polyether liquid, and urethane powder at various compositions. The polyether liquid used here was polytetramethylene glycol modified with phenyl isocyanate, and the powdér was urethane derivative of 4,4′-diphenylmethane diisocyanate. Under certain conditions, some of the ternary blends showed larger increase of viscosity under an electric field than those of binary mixtures prepared from each component of the ternary one. In this case, the viscous polyether and urethane powder act cooperatively by forming some particular structures within the blends. Microscopic observation revealed that each urethane particle was covered with polyether liquid in the absence of electric field, and that the binary droplets aggregated to form viscous bridges between the electrodes keeping powders within them.