A NEW NET-LIKE STRUCTURE FORMED BY A METAL OIL ELECTRORHEOLOGICAL FLUID/

A new kind of net-like structure formed by the metal spheres suspended in a metal/oil electrorheological (ER) fluid is reported for the firs t time in this Letter. The experimental results show that this structu re is totally different from that formed by dielectric particles. Afte r comparing the two formation patterns, it is found that the dielectri c particles in certain ER fluids align themselves into chains or colum ns in the direction of the external electric field. The metal particle s in a metal/oil ER fluid, on the other hand, form a net-like structur e of chains and no column could be observed even when the ER fluid has been exposed to a high electric field. We attribute the net-like stru cture of the metal ER fluid to the strong interaction between dipole f ields induced on the metal particles under the external electric field , Finally, the dielectric properties of the different structures were measured and are discussed in this paper. (C) 1996 American Institute of Physics.