Phase separation dynamics in binary fluids containing quenched or mobile filler particles

The dynamics of phase separation of binary fluids in the presence of quenched or mobile filler particles, with preferential attraction for one of the two fluid components, is investigated by means of extensive molecular dynamics simulations in two dimensions. When the filler particles are quenched, we found that they lead to a slowing-down of the kinetics that is enhanced as the density of the filler particles is increased. The domain growth in this case is found to follow a crossover scaling form which links domain growth in pure binary mixtures to that in the presence of quenched filler particles. On the other hand, when the filler particles are annealed, systematic simulations for various values of single filler particle mass, mu(c), and filler particle density, rho(c), show that the filler particles only affect the nonuniversal prefactor of the power law. The power law itself remains given by t(2/3), characteristic of inertial growth that is typically observed in pure binary fluid mixtures. The prefactor is found to depend on mu(c) as mu(c)(-1/3) as expected in phase separating fluid in the inertial regime. (C) 2003 American Institute of Physics.