Defoamer mechanism of action
Any factor that can destroy the stability of foam can be used for defoaming. Defoaming covers two factors: “foam suppression” and “foam breaking”. Silicone defoamers have this function. They can reduce the surface tension of water, solutions, suspensions, etc., prevent the formation of foam, or reduce the original foam, and usually have a selective effect. Generally, physical defoaming methods are difficult to defoam instantly, while chemical interface defoaming is very fast, convenient and efficient. In short, defoamers refer to agents with chemical and interface chemical defoaming effects. The process of “foam suppression” and “foam breaking” of defoamers is: when the defoamer is added to the system, its molecules are randomly distributed on the surface of the liquid, inhibiting the formation of an elastic film, that is, terminating the generation of foam. When a large amount of foam is generated in the system, the defoamer is added, and its molecules are immediately spread on the surface of the foam, spreading rapidly to form a very thin double film layer, which further diffuses, penetrates, and invades in layers, thereby replacing the original foam film wall. Due to its low surface tension, it flows to the liquid with high surface tension that produces foam. In this way, the defoamer molecules with low surface tension continue to diffuse and penetrate between the gas-liquid interface, making its membrane wall thinner rapidly. At the same time, the foam is strongly pulled by the surrounding membrane layer with high surface tension, which causes the stress around the foam to be unbalanced, thus causing it to “break”. The Tianjin defoamer molecules that are insoluble in the system re-enter the surface of another foam membrane, and this is repeated until all the foams are destroyed.
