Structuration and elasticity of electrorheological fluids

Abstract

Solid particles suspended in a liquid phase can build linear structures when a large enough electric field is applied to the suspension. These structures confer to the suspension a shear modulus G, which is measured with an oscillating plate device. This system allows to simultaneously visualize the change of structure of the suspension. We observe an important decrease of G with the amplitude of the strain, and explain it by the behavior of the forces between two conductive particles at short separations. Striking features relative to stripe formation upon large amplitude strain and subsequent considerable increase of elasticity are reported.