Abstract
Foams are dispersed systems of gas particles. The stability of the foams, however, is determined by the property of foam membrane. Foams should, therefore, be studied as membrane systems. In this paper, fundamental properties of the foams are discussed on the basis of the surface chemical behavior of the membrane systems. Besides very stable foams covered with solid films or bimolecular films, less stable foams as well as unstable foams are stabilized by the adsorbed monolayer of foaming agent. These foams are the more stable if the more of the foaming agent is adsorbed the more tightly. Antifoams are classified into foam breakers and foam inhibitors. The foam breaker acts upon the foams already formed, by spreading on the surface of the foam membrane. On the other hand, the foam inhibitor acts to prevent foaming by driving out the foaming agent from the surface of the foam membrane as the result of preferential adsorption.
