Direct measurement of the variation of double-layer repulsion with distance

Abstract

Soap films can be subjected to compressive stresses exceeding 1 atm while their thickness is measured optically in an apparatus which is described in detail. It permits forming the film within a ring of porous porcelain whose pores communicate to the outside, whereas the film is in an enclosure in which the air pressure can be varied. The applied pressure is balanced primarily by the doublelayer repulsion between the monolayers of the film. Hence as the pressure is increased, the f i l m thickness decreases showing how double-layer repulsion varies with the distance between the monolayers. The agreement with theory is satisfactory as far as it pertains to the region of low potentials which determines the slopes of the distance dependence. The absolute values involve the less certain high potential region of the theory as well as assumptions about the structure of the films but can be brought into reasonable agreement. The effect of van der Waals forces can also be seen at higher ionic strengths.

Effect of polyelectrolytes on (de)stability of liquid foam films

“…It can be measured with a Thin Film Pressure Balance (TFPB) in dependence of the lm thickness h resulting in a disjoining pressure isotherm P(h). The TFPB with porous plate technique was developed by Mysels 4 and Exerowa. 5,6 It is mainly used to study foam lms, but recently it has been also extended to study wetting lms.…”

Studying bubble–particle interactions by zeta potential distribution analysis

“…To support the experimental observations, the classical DLVO-type of interaction between an air bubble and alumina particle at pH 6.5, 8.5 and 11 in the presence of 0.1 mM DF250 were considered. In this study, the electrostatic double layer forces were calculated using the constant potential boundary conditions of air bubble and alumina particle: [2,3] [1]…”

“…[2,3] However, the interaction behavior as theoretically described by DLVO is somewhat limited when considering a wide variety of interaction phenomena at short-range. Non-DLVO forces that are understood to a lesser extent can become dominant, shielding the predicted DLVO-type behavior.…”

Surface adsorption of sulfonated poly(phenylene sulfone)/C14TAB mixtures and its correlation with foam film stability

“…33 Thin film pressure balance Disjoining pressure isotherms were measured with porous plates and the thin film pressure balance (TFPB) technique. 34,35 With this method free-standing horizontal liquid foam films can be investigated. Thus, information about interaction forces, thicknesses, drainage and stabilities of thin foam films are accessible.…”