The gravity approach and coalescence of fluid drops at liquid interfaces

Abstract

AbstractThe rate of thinning of the liquid film trapped between a fluid drop and a liquid interface and the subsequent coalescence of the drop were investigated using an interferometric method. The rate of film thinning for small drops was in good agreement over a narrow range of film thickness with two previously proposed models. The rate was greater than predicted when the film thickness was less than 0.2 μ presumably because of movement of the interfaces. The minimum thickness in the film at rupture was usually less than 500 Å. for drop diameters up to 2500 μ. The seemingly anomalous behavior of drops previously observed in a partial coalescence series resulted from uneven film thinning with larger drops. Partial coalescence between finite drops was investigated briefly; no secondary drop was produced when the drop diameter ratio was less than about 3.5.