Anti-fog

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.

Application

Initially developed by NASA for space helmet visors and aircraft windshields.

Anti-fog agents are usually available as spray solutions, cremes 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 .

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
• Hydrophilic coatings that maximize the surface energy:
• Hydrophilic polymers and hydrogels:
• Gelatin
• 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. Other home recipes exist, including the not effective application of vinegar or ammonia.

See also

• Fog
• Fogging (photography) for fogging artifacts in photography

References

External links