Foam stability thermodynamic factors

Indeed, a direct relationship between the lifetimes of films and foams and the mechanical properties of the adsorption layers has been proven to exist [e.g. 13,39,61-63], A decrease in stability with the increase in surface viscosity and layer strength has been reported in some earlier works. The structural-mechanical factor in the various systems, for instance, in multilayer stratified films, protein systems, liquid crystals, could act in either directions it might stabilise or destabilise them. Hence, quantitative data about the effect of this factor on the kinetics of thinning, ability (or inability) to form equilibrium films, especially black films, response to the external local disturbances, etc. could be derived only when it is considered along with the other stabilising (kinetic and thermodynamic) factors. Similar quantitative relations have not been established yet. Evidence on this influence can be found in [e.g. 2,13,39,44,63-65]. 

Stability of foams and other disperse systems holds a central position in colloid chemistry. Nevertheless, many aspects of this problem are not completely clear. There is no theory as yet that can offer a thorough quantitative explanation of the behaviour of foams with time. It is hardly possible to create such a unified theory, since the dominant thermodynamic and kinetic factors of stability can be different for the different foams. 

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