Goggles and windshields are very important safety items that must remain perfectly clear for good visibility. If they fog up, then they are no longer safe and become a danger rather than a protection. Unfortunately, it is something that can happen easily if there’s a difference in temperature or humidity.
The current method to address this issue is by using electricity, which requires a battery, or by applying a water-repelling coating, which wears off. However, the way of the future is with light, which is much more convenient. This new anti-fog coating that warms up the surface using light instead of electricity was developed by researchers at ETH Zurich. The research was published in the journal Nano Letters.
The design works like a heating element that doesn’t need to be plugged in. The team says the coating cranks up the heat by 3°C or 4°C (5.4°F to 7.2°F). Testing of their coating proved that heat increase can clear fog four times faster than regular anti-fog sprays.
The coating contains gold nanoparticles embedded in titanium oxide. It catches the infrared part of sunlight and a portion of visible light and heats up the surface, thus preventing condensation. The coating is fully transparent.
That’s actually what makes this coating so special. See, normally, it’s dark surfaces that absorb light and convert it into heat, but this is a transparent surface that has the same effect. Also, since this mechanism is built in, the new coating should keep working for much longer than typical coatings.
Christopher Walker, lead author of the study, says:
“Spray treatments often lose their effect after a while because the anti-fog film dries up or becomes unevenly distributed. A durable coating like ours lasts much longer than a spray treatment, which you have to apply virtually on a daily basis.”
Their coating is especially suitable for wearable items such as glasses and goggles since the only energy source required is the sun. However, some people are skeptical about how well it works outside of direct sunlight. In the lab, other light sources were shown to have the same effect, but what about if there’s very little light? How well would it perform, then?
The team is now looking to develop the technology further in order to commercialize it. They describe the coating in the video below:
