Repulsive Van Der Waals Interactions: Their Role in Various Separation Methods

Abstract

Abstract It has long been surmised, as a theoretical curiosity, that conditions could arise under which the sign of the van der Waals interaction between two different uncharged bodies, surrounded by a liquid, might be negative, i.e. that such bodies would repel each other. This possibility is implicit in Hamaker's classical paper on van der Waals-London interactions, although, remarkably enough, Hamaker somehow became persuaded that this view was erroneous, and wrote his paper with the apparent purpose to gainsay it: “If two particles are embedded in a fluid and the London-van der Walls force between particles and fluid is greater than between the particles themselves, it might be thought that the resultant action will be a repulsion rather than an attraction. As has been pointed out to the author by Dr. J.H. de Boer, this conclusion does not hold. Owing to a peculiar property of the London-van der Waals forces, the resultant force is generally attractive even when the particles are surrounded by fluid. ...