Disjoining pressure in thin liquid foam and emulsion films—new concepts and perspectives

Abstract

The present review is a topical survey of the disjoining pressure in thin liquid foam and emulsion films from both the experimental and the theoretical points of view. Section 2 deals with the latest research work on experimental techniques with which the disjoining pressure Π in foam, emulsion, and pseudo-emulsion films can be measured. Although a lot of techniques are available, the question of the origin of the charges at the water/air and the water/oil interfaces of films, which are stabilized by non-ionic surfactants, has not yet been answered. We address this question in section 3, reviewing the latest relevant literature. The relevance of structural forces for the disjoining pressure is outlined in section 4, which focuses on films which are stabilized by surfactant/polyelectrolyte mixtures.

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

“…More detailed information about TFPB and interaction in foam lms are given in former reviews. 7,9,10 By increasing the pressure within the cell against the atmospheric pressure the lm starts to drain until repulsive interactions (positive disjoining pressure) between the opposing surfaces prevents further thinning. In mechanical equilibrium the disjoining pressure compensates the capillary pressure.…”

Structures and Properties of Newton Black Films Characterized Using Molecular Dynamics Simulations

“…A number of investigations [1][2][3][4][5] have been made into foam systems because of important applications of foam in our daily life (i.e., fire-fighting foam, polymeric foam insulation, foam rubbers, and personal care products). Many aspects of foam, particularly the structure and properties of the NBF, need further investigation.…”

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

“…4 shows disjoining pressure isotherms of sPSO 2 -220/ C 14 TAB at different sPSO 2 -220 concentrations and fixed C 14 From the slope of the isotherms the Debye length k exp À1 and ionic strength I exp were extracted (Table 1). 36 The experimentally determined ionic strength I exp is compared in Table 1 to the maximum ionic strength I max and the complex ionic strength I complex . I max is the ionic strength of the system when one assumes complete dissociation, while I complex is the ionic strength of the system assuming complete dissociation and 1 : 1 binding between polyelectrolytes and surfactants.…”