Adsorption of inorganic ions in black foam films

Abstract

The concentration of inorganic ions adsorbed in the thin aqueous core(∼20 Å) of black films at their limiting thickness has been measured directly by a radiotracer method and compared with the results obtained from film conductance measurements. The standard free energy of adsorption (2-3 RT/mole) is comparable to that observed for the adsorption of inorganic ions on monolayers at the bulk solution interface. It is suggested that the stability of these very thin films is determined by the work required to desorb water molecules from the aqueous core.