Modeling of surface phenomena in the presence of surface-active agents on the basis of the density-functional theory

Within the framework of the density-functionalmethod in multiphase multicomponent mixture hydrodynamics, the possibility of modeling surface-active agents on a “fluid-fluid” phase interface is shown. The method is based on the continuum description of multiphase mixtures with introducing terms quadratic in component density gradients to entropy or free energy. The determining equations are derived. Hydrodynamic model problems which demonstrate certain typical phenomena (the accumulation of surface-active agents on the phase interface, the corresponding decrease in surface tension, and the Gibbs and Marangoni effects) are solved numerically.