Warming gold nanofilm can stop glasses fogging-up

A transparent antifogging coating for glasses and other lenses that works by selectively absorbing the infrared wavelengths in sunlight has been developed by researchers in Switzerland. The material, which heats the surface to prevent condensation, is readily scalable and durable and could solve many issues that plague current antifogging technologies.

Fogging occurs when warm, moist air encounters a relatively cold surface, causing water vapour to condense. Most commercial antifogging coatings work by making the surface superhydrophilic, causing the droplets to spread out into a thin film. Unfortunately, such coatings also attract contaminants. An alternative is to make the surface superhydrophobic to prevent droplets from sticking at all, but this requires the creation of a nanopatterned surface: ‘It’s really hard to find a durable, scalable coating which is superhydrophobic on glass,’ says Iwan Hächler of ETH Zurich.