Kinetics of Phase Separation in Thin Films: Simulations for the Diffusive Case

Abstract

We study the diffusion-driven kinetics of phase separation of a symmetric binary mixture (AB), confined in a thin-film geometry between two parallel walls. We consider cases where (a) both walls preferentially attract the same component (A), and (b) one wall attracts A and the other wall attracts B (with the same strength). We focus on the interplay of phase separation and wetting at the walls, which is referred to as {\it surface-directed spinodal decomposition} (SDSD). The formation of SDSD waves at the two surfaces, with wave-vectors oriented perpendicular to them, often results in a metastable layered state (also referred to as ``stratified morphology''). This state is reminiscent of the situation where the thin film is still in the one-phase region but the surfaces are completely wet, and hence coated with thick wetting layers. This metastable state decays by spinodal fluctuations and crosses over to an asymptotic growth regime characterized by the lateral coarsening of pancake-like domains. These pancakes may or may not be coated by precursors of wetting layers. We use Langevin simulations to study this crossover and the growth kinetics in the asymptotic coarsening regime.

39 pages, 19 figures, submitted to Phys.Rev.E

References in corpus (6)

• 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
• Interface localisation-delocalisation transition in a symmetric polymer blend: a finite-size scaling Monte Carlo study
• Non-monotonous crossover between capillary condensation and interface localisation/delocalisation transition in binary polymer blends
• Surface-Directed Spinodal Decomposition in Binary Fluid Mixtures
• Finite size effects on the phase diagram of a binary mixture confined between competing walls

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• Spinodal Decomposition in Thin Films: Molecular Dynamics Simulations of a Binary Lennard-Jones Fluid Mixture
• Nucleation and Growth of Droplets in Vapor-Liquid Transitions
• 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
• Surface-directed spinodal decomposition in the pseudobinary alloy (HfO_2)_x(SiO_2)_{1-x}
• Kinetics of Phase Separation in Thin Films: Lattice versus Continuum Models for Solid Binary Mixtures
• Dynamical Effects and Phase Separation in Thin Films
• Effect of bond-disorder on the phase-separation kinetics of binary mixtures: a Monte Carlo simulation study