Spinodal Decomposition in Thin Films: Molecular Dynamics Simulations of a Binary Lennard-Jones Fluid Mixture

Abstract

We use molecular dynamics (MD) to simulate an unstable homogeneous mixture of binary fluids (AB), confined in a slit pore of width $D$. The pore walls are assumed to be flat and structureless, and attract one component of the mixture (A) with the same strength. The pair-wise interactions between the particles is modeled by the Lennard-Jones potential, with symmetric parameters that lead to a miscibility gap in the bulk. In the thin-film geometry, an interesting interplay occurs between surface enrichment and phase separation. We study the evolution of a mixture with equal amounts of A and B, which is rendered unstable by a temperature quench. We find that A-rich surface enrichment layers form quickly during the early stages of the evolution, causing a depletion of A in the inner regions of the film. These surface-directed concentration profiles propagate from the walls towards the center of the film, resulting in a transient layered structure. This layered state breaks up into a columnar state, which is characterized by the lateral coarsening of cylindrical domains. The qualitative features of this process resemble results from previous studies of diffusive Ginzburg-Landau-type models [S.~K. Das, S. Puri, J. Horbach, and K. Binder, Phys. Rev. E {\bf 72}, 061603 (2005)], but quantitative aspects differ markedly. The relation to spinodal decomposition in a strictly 2-$d$ geometry is also discussed.

37 pages, 11 figures, to appear in Phys. Rev. E

References in corpus (17)

• Theory of Phase Ordering Kinetics
• Inertial effects in three dimensional spinodal decomposition of a symmetric binary fluid mixture: A lattice Boltzmann study
• Modelling droplets on superhydrophobic surfaces: equilibrium states and transitions
• Molecular Dynamics Simulations
• Lattice Boltzmann simulations of contact line motion in a liquid-gas system
• Breakdown of scale-invariance in the coarsening of phase-separating binary fluids
• 3D Spinodal Decomposition in the Inertial Regime
• Hydrodynamic Spinodal Decomposition: Growth Kinetics and Scaling Functions
• Quantitative study of laterally inhomogeneous wetting films
• Molecular Dynamics Simulation of Spinodal Decomposition in Three-Dimensional Binary Fluids
• Wetting and Capillary Condensation in Symmetric Polymer Blends: A comparison between Monte Carlo Simulations and Self-Consistent Field Calculations
• Transport phenomena and microscopic structure in partially miscible binary fluids: A simulation study of the symmetrical Lennard-Jones mixture
• Kinetics of Phase Separation in Thin Films: Simulations for the Diffusive Case
• Spinodal Decomposition in Binary Gases
• Spinodal decomposition in fluids: diffusive, viscous and inertial regimes
• Tests of Dynamical Scaling in 3-D Spinodal Decomposition
• Phase ordering of two-dimensional symmetric binary fluids: a droplet scaling state

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• Aging and Crossovers in Phase-Separating Fluid Mixtures
• Phase separation of an asymmetric binary fluid mixture confined in a nanoscopic slit pore: Molecular-dynamics simulations
• Phase separation in a binary mixture confined between symmetric parallel plates: Capillary condensation transition near the bulk critical point
• Kinetics of Phase Separation in Thin Films: Lattice versus Continuum Models for Solid Binary Mixtures
• Kinetics of Surface Enrichment: A Molecular Dynamics Study
• Critical surface adsorption of confined binary liquids with locally conserved mass and composition
• Non-equilibrium diffusion characteristics of a particle system and the correspondence to a social system