Antifoams work in a multi-step method that involves dispersing particles of chemical substances, such as silica particles or ethylene-bis-stearamide, across the surfaces of bubbles to eliminate them. As the particles hit the surfaces of the bubbles, they cause the bubbles to gradually shrink, float to the surface of the water and dissipate. Antifoamers, also called defoamers, are typically silicone-based, although some are primarily comprised of oils.
When first released onto a surface, defoamers set to work by quickly separating oil thins along walls or in crevices. This allows for the separation of compounds on the affected surface, such as oil and hydrophobic silica. These elements are broken down by defoamers, which act as water-insoluble surfactants. Defoamers, when used correctly, help to bring bubbles to the surfaces of water surfaces, where they can then split and dissipate. As with other surfactants, however, the key to making defoamers work properly requires using the appropriate amount. Using too much defoamer may impair the ability of sizing agents and dry strength agents to carry out their functions. Excess defoamer can also exacerbate problems of residual buildup, and ultimately do more harm than good. Using too little defoamer, however, can reduce the drainage capacity of certain substances, and cause the loss of important absorbent materials.