Mechanisms of defoaming and antifoaming
Defoamers and defoaming agents - Mechanisms of action

When an antifoam is added to a formulation, it first forms an emulsion of droplets which act on the individual liquid films, destroying the foam. Two mechanisms are involved in this destruction: the oil droplet spreads at the air/liquid interface and causes thinning of the film by entrainment of the underlying fluid, or film thinning is driven by de-wetting of the hydrophobic antifoam droplet (film pinching or bridging).

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