COMPUTER-SIMULATIONS OF NONEQUILIBRIUM STRUCTURE FORMATION IN ELECTRORHEOLOGICAL FLUIDS

The temporal evolution of three-dimensional structure in an electrorhe ological fluid under nonequilibrium, high-field conditions is examined by a computer-simulation method similar to that of Klingenberg, van S wol, and Zukoski [J. Chem. Phys. 91, 7888 (1989)]. A variety of charac teristic real-space properties (e.g., the radial distribution function ) and the static structure factor S(q) are monitored during the simula tion. The field-induced polarization of particles causes rapid chain f ormation followed by a kinetic trapping into a complicated gel-like st ate with no obvious lateral ordering. For all volume fractions conside red, the first percolating chain appears at ten times the average time to first contact. Quenching of the gel is nearly complete on an order of magnitude longer time scale. The formation of chains results in th e growth and narrowing of Bragg-like peaks in S(q) along the field dir ection. In the direction perpendicular to the field, the first peak in S(q) also grows and shifts to smaller q.