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.
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Application
Initially developed by NASA for space helmet visors and aircraft windshields.
Anti-fog agents are usually available as spray solutions, creams and gels, and wet tissues. More resistant coatings are often applied in complex manufacturing processes. Anti-fog additives can also be added to plastics where they exude from the inside to the surface [1].
Agents
The following substances are used as anti-fog agents:
- Surfactants that minimize the surface tension of the water:
- 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:
- Hydrophilic polymers and hydrogels:
- Hydrophilic colloids and nanoparticles:
- Titanium dioxide, becomes highly hydrophilic under UV light
Home recipes
The easiest method to prevent fogging is to apply a thin film of detergent. Another method common among divers is to use saliva, which can also be used in car windows. Other home recipes exist, including the most effective application of vinegar or ammonia.
See also
- Fog
- Fogging (photography) for fogging artifacts in photography
References
External links
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