How does antifogging work?

Answer 1

Anti-fog agents, also known as anti-fogging agents and treatments, prevent the condensation of water on a surface in the form of small droplets which resemble fog. Anti-fog treatments are often used for transparent glass or plastic surfaces in optics, such as the lenses and mirrors found in glasses, goggles, camera objectives, and binoculars. Anti-fog treatments work by minimizing surface tension, resulting in a non-scattering film of water instead of single droplets, an effect called wetting. Anti-fog treatments usually work either by application of a surfactant film or by creating a hydrophilic surface.

The following substances are used as anti-fog agents:

* Surfactants that minimize the surface tension of the water, such as detergents, including shampoo and soap, applied as a solution and wiped off without rinsing * Shaving cream applied and wiped off without rinsing * Hydrophilic coatings that maximize the surface energy such as Gelatin or titanium dioxide, becomes highly hydrophilic under UV light The easiest method to prevent fogging is to apply a thin film of detergent. Another method common among divers is to use saliva. Other home recipes exist, including the most effective application of vinegar or ammonia. The chemicals found in RainX and many other commercial products mimic the above substances, except they are generally more resistant to weathering and last longer. For example, RainX uses ionized and acidified alcohol and silicone-based compounds to prevent beading and reduce surface tension. Aquapel is a rain repellent glass treatment created by PPG Industries. It is a competitor to the more widely known Rain-X product, but unlike Rain-X, is not a silicone-based compound. Aquapel Glass Treatment consists of fluorinated compounds which create a chemical bond with glass surfaces, causing water to bead up and roll off. Because of this chemical bond with glass, Aquapel is reported to last much longer than silicone-based rain repellents.