How does foaming occur?

Foam / Froth occurs when a gas molecule gets introduced in a solution. In unadulterated fluids, froth is unstable to heat and pressure change, and any air gap quickly ascend to the surface and burst.

What makes up a Defoamer?

A Surfactant for its low surface tension, An Emulsifier for its dispersibility, An Emulsifying Additive for stabilization and A Carrier for better diffusion.

Working of a Defoamer

Defoamer additive inhibits the liquid-gas interaction, easily breaks down the froth structure and efficiently negates the stabilization of the same. It also prevents the impurities to take part in any kind of reaction with the liquid, controlling the inimical effects of foam. The working chemistry behind any defoamer is its halfway dissolvability. At initial instance, the defoamer additives pierce down into the polyanion film, decreasing its surface tension. Since, the external surface tension around the froth is much higher, this osmotic phenomenon causes cracks. Secondly, this additive forces itself into froth's mono molecule membrane, keeping it to maximum till it completely ruptures.