THE DRAINAGE OF FREE LIQUID-FILMS

A review is presented of the present theoretical understanding of the thinning of free liquid films by marginal regeneration. The theory of this phenomenon, introduced by Mysels et al. (K.J. Mysels, K. Shinoda and S. Frankel, Soap Films, Studies of their Thinning and a Bibliograp hy, Pergamon, New York, 1959) is modified so as to understand its dire ction dependence, i.e. the difference between marginal regeneration ph enomena at the top, bottom and vertical side Plateau borders in a vert ical film. A central role is played by squeezing-mode surface waves; t his leads also to an understanding of the thinning of horizontal films . The thinning rate of a film is shown to be related to the bulk visco sity of the liquid phase involved.