Three mechanisms of action of defoamers during defoaming process

Many harmful foam will be produced in the process of industrial production, and defoamers need to be added at this time. The application of defoamers is also very extensive. Long term defoaming, also known as foam suppression, is the most important indicator of the quality of defoamers. In most cases, we use defoamers because of their anti foaming properties, rather than their initial defoaming ability. Defoaming and foam suppression are relative, and products with good defoaming performance may have lower foam suppression performance. In practical applications, it depends on the specific situation. And below, the editor of Jianyi Chemical will introduce to you the three mechanisms of action of defoamers during the defoaming process!

Breaking bubbles:Relative to foam (foam polymer), it will invade the foam from the air side and destroy the foam integration.

Bubble suppression:Intrusion into the foam from the liquid side will destroy the foam integration, making it difficult to produce foam.
Defoaming:Invade the bubble from its interface, causing the bubble to merge and float out of the liquid surface.

1. Breaking bubbles
After the defoamer adsorbs onto the bubbles, it invades the bubble membrane due to surface tension. Subsequently, the surface tension caused by the expansion of the defoamer on the surface of the foam film resulted in thinning of the foam film, thereby damaging it.

2. Foam suppression
Both foam suppressants and foaming substances in the liquid are adsorbed onto the foam film simultaneously. The surface tension of the foam film decreases due to the adsorption of anti foaming agents, causing the foam film to become thinner. As a result, the unstable bubble film surfaced and was destroyed.

3. Defoaming
The defoamer adsorbs onto the foam film in the liquid. After the various bubbles in the liquid adsorb to each other, the adsorption interface is destroyed and a large bubble is formed. The large bubbles with increased buoyancy quickly rise to the liquid surface.

The molecular structure, molecular weight, hydrophobicity, and other differences of wetting and dispersing agents result in varying strengths in terms of wetting and dispersing ability, foam stability, anti settling, water resistance, and color development. Therefore, in different types of formulations, there are different focuses on the selection of wetting and dispersing agents.