STRUCTURES OF AN ELECTRORHEOLOGICAL FLUID

Extensive computer simulations were carried out to examine the structu res of electrorheological (ER) fluids. In a weak electric field, ER fl uids move from a Liquid state to a nematic-liquid-crystal state that h as ordering only in the field direction. If the electric field is stro ng and thermal fluctuations are weak or moderate, ER fluids develop in to a body-centered-tetragonal lattice. A very strong electric field wi th very weak or no thermal fluctuations may force ER fluids into a pol ycrystalline structure. When both the electric field and thermal fluct uation are strong, ER fluids develop into a glasslike state, in which the particles aggregate together to form thick columns, but the struct ure has no appreciable ordering. The simulation has also shown that th e solidification time and chain formation time in ER fluid systems dep end mainly on the ratio of the viscous force to the dipolar force.