Kinetics of Surface Enrichment: A Molecular Dynamics Study

Abstract

We use molecular dynamics (MD) to study the kinetics of surface enrichment (SE) in a stable homogeneous mixture (AB), placed in contact with a surface which preferentially attracts A. The SE profiles show a characteristic double-exponential behavior with two length scales: ξ_-, which rapidly saturates to its equilibrium value, and ξ_+, which diverges as a power-law with time (ξ_+ \sim t^θ). We find that hydrodynamic effects result in a crossover of the growth exponent from θ\simeq 0.5 to θ\simeq 1.0. There is also a corresponding crossover in the growth dynamics of the SE-layer thickness.

20 pages, 6 figures, Published in J. Chem. Phys. (Research Highlights)