Microscopic theory for interface fluctuations in binary liquid mixtures

Abstract

Thermally excited capillary waves at fluid interfaces in binary liquid mixtures exhibit simultaneously both density and composition fluctuations. Based on a density functional theory for inhomogeneous binary liquid mixtures we derive an effective wavelength dependent Hamiltonian for fluid interfaces in these systems beyond the standard capillary-wave model. Explicit expressions are obtained for the surface tension, the bending rigidities, and the coupling constants of compositional capillary waves in terms of the profiles of the two number densities characterizing the mixture. These results lead to predictions for grazing-incidence x-ray scattering experiments at such interfaces.

23 pages, 11 figures

References in corpus (3)

• Capillary Waves in a Colloid-Polymer Interface
• Global phase diagrams of binary dipolar fluid mixtures
• Local orientations of fluctuating fluid interfaces

Cited by in corpus (8)

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• Effective Hamiltonian for fluid membranes in the presence of long-ranged forces
• Intrinsic structure of liquid surface and capillary waves on the Density Functional Theory