S. Tcholakova et al., van der Waals interaction between two truncated spheres covered by a uniform layer (deformed drops, vesicles, or bubbles), LANGMUIR, 17(8), 2001, pp. 2357-2362
In this paper, we derive explicit expressions for the van der Waals interac
tion energy and force between two truncated spheres covered by a thin layer
of uniform thickness. These expressions can be used for description of the
interactions in dispersions of deformable particles (emulsions, vesicle su
spensions, and foams). As an illustration of the applicability of these for
mulas to real systems, we consider the interaction between micrometer-sized
oil drops, covered by a protein adsorption layer, in oil-in-water emulsion
s. The Hamaker constants for the interactions between protein, oil, and wat
er are calculated from literature data. The equilibrium radius and thicknes
s of the liquid film, which forms upon the collision of two emulsion drops,
are determined as functions of the drop size and electrolyte concentration
. From the parameters of the equilibrium films, we calculate the total inte
raction energy between the drops. The numerical results show that both fact
ors, the presence of the protein layer and the drop deformation, have a sig
nificant effect on the pair interaction energy.