A defoamer is a chemical that reduces foam formation and stability in a liquid. They are commonly used in a variety of industrial and laboratory applications to prevent excessive foaming of liquids.

The role of defoamer is to destroy or inhibit the foam film on the surface of the liquid, so that the foam quickly dissipates or is not easy to form. Therefore, it can be said that defoamer plays a role in defoaming.

Common antifoamers include silicone oil, fatty alcohol, degassing agents, etc., which can be added to the liquid or sprayed.