ANISOTROPIC DIELECTRIC-PROPERTIES OF STRUCTURED ELECTRORHEOLOGICAL FLUIDS

We present an approach to monitor the structure-induced anisotropic di electric properties of electrorheological fluids. The particles used a re made from uniform glass microspheres coated with an inner magnetic layer and an outer dielectric layer. Under an applied magnetic field, the particles are found to form columnar structures with a body-center ed-tetragonal crystalline arrangement inside the columns. It is shown that the structure-induced dielectric constant can be consistently exp lained through first-principles calculations. (C) 1998 American Instit ute of Physics. [S0003-6951(98)04647-6].