Forces between a hard surface and an air-aqueous interface with and without films

The adsorption of particles to air-aqueous interfaces is vital in many applications, such as mineral flotation and the stabilization of food foams. The forces in the system determine whether a particle will attach to an air-aqueous interface. The forces between a particle and an air-aqueous interface are influenced by Derjaguin-Landau-Verwey-Overbeek forces (i.e. van der Waals and electrostatic forces), non-Derjaguin-Landau-Verwey-Overbeek forces (e.g. hydrophobic, hydrodynamic, structural, and capillary forces), liquid drainage, and liquid flow. As an air-aqueous interface can be deformed by a particle, the forces measured between an air-aqueous interface and a particle can differ from those measured between two hard surfaces separated by liquid. The presence of a film at an air-aqueous interface can also change the forces.