ABSTRACT
Foam consists of a high-volume fraction of gas dispersed in a liquid. Because of the high-volume fraction of the gas phase, the gas bubbles in foam are distorted in the form of polyhedra separated by thin liquid films. The drainage of the continuous phase leads to profiles of the dispersed-phase volume fraction and of the film thickness. The drainage of the continuous-phase liquid from the thin films and the Plateau borders will continue until the system reaches mechanical equilibrium, after which it ceases. For an equilibrium film, the Plateau border suction for film drainage is exactly counterbalanced by the disjoining pressure. The profile of the equilibrium film thickness can then be calculated from the relationship between the film thickness and the disjoining pressure. In a standing foam or concentrated emulsion, the continuous-phase liquid in the thin films drains into the neighboring Plateau borders under the action of Plateau border suction.
