Anti-fog additives are used as masterbatch during the production process to prevent fog formation on the polycarbonate sheets in greenhouses. This type of polycarbonate sheet is mainly used in food packaging and agricultural industries. Anti-fog additives are made of molecules with both polar and nonpolar ends. The presence of polar groups on the surface improves the wetting of polycarbonate sheets. The wetting of the sheet with water is improved as the surface tension of water with the polycarbonate sheet is reduced. In other words, a liquid can effectively wet a solid surface when the contact angle between the liquid and solid surface is very small.
An anti-fog additive reduces the difference between the surface tensions of water and the sheet so that the contact angle of the water droplet with the polymer surface would be minimum. This, in turn, reduces the inside reflection of the incident light in the water droplets, leading to higher sheet transparency. Anti-fog additives cause further light transmission, reduce water droplet accumulation, control pests, and promote plant growth.