Oscillatory structural forces probed by the nanofilm Macroscopic contact angle

Abstract

The research on oscillatory structural forces (OSF) has a long history. OSF arise when liquid dispersions of a nano/micellar solution of complex fluids are confined between surfaces. In recent years, significant progress has been made in the measuring and modeling of OSF. Advanced techniques that use tools such as the surface forces apparatus (SFA), colloidal probe atomic force microscope (CP-AFM), and foam film capillary balance (FCB) were developed to gain information about nanofilm interactions in the confinement film geometry as the “layer” and “in-layer” particle entropy structural transition takes place. Henderson’s theory, based on the statistical mechanics approach to model the OSF, proposed analytical results using the Laplace transformation of the radial distribution function (RDF) for two large hard spheres in a fluid to calculate the film free energy; this approach is commonly applied to the model of the nanofilm layering between two solid surfaces. To extend Henderson’s theory to model the “layer” and “in-layer” structural transition of a capillary system, e.g., foam and emulsions, we propose the use of the foam film-meniscus macroscopic contact angle approach to calculate the nanofilm’s OSF.