Spinodal Decomposition In Binary Fluids Research Articles

Domain formation and growth in spinodal decomposition of a binary fluid by molecular dynamics simulations

The two initial stages of spinodal decomposition of a symmetric binary Lennard-Jones fluid have been simulated by molecular dynamics simulations, using a hydrodynamics-conserving thermostat. By analyzing the growth of the average domain size R(t) with time, a satisfactory agreement is found with the R(t) proportional t1/3 Lifshitz-Slyozov growth law for the early diffusion-driven stage of domain formation in a quenched homogeneous mixture. In the subsequent stage of viscous-dominated growth, the mean domain size appears to follow the linear growth law predicted by Siggia.

Spinodal Decomposition in Two-Dimensional Binary Fluids

We use lattice-Boltzmann simulations to examine late stage spinodal decomposition in binary fluids, showing that the scaling hypothesis for phase ordering does not hold in all cases. We also examine the effects of an applied shear on the coarsening of the spinodal pattern.

Spinodal decomposition in binary fluids under shear flow

We discuss the effects of shear rates on the structure, rheology and kinetics of phase separation in binary fluids through numerical Langevin simulations in both two- and three-dimensions. Our major findings are as follows: (1) shear flow distorts the isotropy properties in normal spinodal decomposition. Under stronger shear, a string phase appears; (2) domains grow differently in directions parallel and perpendicular to the flow direction; (3) excess shear viscosities due to shear flow have a characteristic peak as a function of shear rates. We compare our findings with the experimental data and simulation results which do not incorporate hydrodynamics.

Slow dynamics in condensed matter: spinodal decomposition and glass transition

A brief review is presented about our recent work on computer studies of a continuum model describing spinodal decomposition of binary fluid, which quantitatively accounts for corresponding experimental results. We then switch over to discussing problems of glass transitions. First we consider the ultraslow mode observed in fragile glass-formers, where the diffusive behavior of this mode is explained in terms of phase dynamics describing slow relaxation of spatial heterogeneous structure resulting from spontaneous break-down of continuous translational symmetry. Next we present a stochastic model for density fluctuation in supercooled liquids, which is mapped onto a certain kinetic lattice gas model which is convenient for Monte Carlo simulation studies.

Late stage spinodal decomposition in binary fluids: comparison between computer simulation and experimental results

Abstract We present detailed comparisons of results on the late stage dynamics of spinodal decomposition obtained by the computer simulation of the time-dependent Ginzburg-Landau equation with hydrodynamic interaction and experiments of a polymer mixture of polybutadiene and polyisoprene. We show that the temporally linear domain growth law, which is characteristic for viscous fluids, is observed in both simulation and experiment in the late stage. Some quantities obtained in such a hydrodynamic domain growth region, such as the interface area density and the scaling function, are compared in detail. Especially, we show that the scaling functions for the two systems are in quantitative agreement.

Late stage dynamics of spinodal decomposition in binary fluid mixtures

Abstract Results of extensive computer simulations of spinodal decomposition in binary fluids with different values of the shear viscosity, which is modeled by the time-dependent Ginzburg-Landau (TDGL) equation with long-range hydrodynamic interaction, are presented. In the low viscosity case, we clearly observe a temporally linear growth law of the characteristic length of domains l(t), namely l(t) ∼ t, in the late stage and confirm that the dynamical scaling law holds in such a hydrodynamic domain growth region. By comparing the scaling functions for different values of the viscosity, we confirm that the scaling function in the hydrodynamic domain growth region does not depend on the viscosity. We also compare the scaling function for fluids with that for the case without hydrodynamic effects, and we establish that the scaling functions for the two systems are different.

Spinodal decomposition in binary fluids: Effects of hydrodynamic interactions.

We propose a computationally efficient method to simulate ordering processes in binary fluids with a long-range hydrodynamic interaction, and the results of a computer simulation of spinodal decomposition in binary fluids in three dimensions using this method are presented. A linear growth law of characteristic length scale l(t), namely l(t)\ensuremath{\sim}t, is observed in the very late scaling stage. The scaling function obtained is in good quantitative agreement with the experiments.