Dissolving interfaces in the presence of gravity

Dynamic surface Light scattering from dissolving interfaces in binary mixtu res of tunable density contrast shows that the surface tension of the inter face between the upper and lower phases of the mixture dissolves more slowl y for a mixture of higher density contrast. Even for a lower density contra st mixture, the dissolution is still slower than would be expected from nai ve application of equilibrium diffusion arguments. The factor most likely t o be responsible for this anomalous dissolution is gravity, through a mecha nism based on the competition between diffusion and sedimentation across th e interface. [S1063-651X(99)02801-9].