Scientists at ETH Zurich have developed a special coating that prevents eyeglass lenses from fogging. Apparently, not all heroes wear capes.
This has been a problem since the advent of optical lenses, but it’s fair to say that it peaked during the pandemic, where everyone who wears glasses learned the hard way that most face masks direct your breath towards your eyes. You’d think someone would fix this by now, but it’s harder than you can imagine.
The difficulty of the problem is evident in the lack of up-to-date solutions. You can wipe your glasses when they fog up, or… well, that’s it. There are anti-fog sprays and special lens coatings that help, but they only minimize the problem.
You don’t need to be a physicist to realize that the best solution is heat. The windows fog up when the hot steam comes into contact with the cold windows. This temperature fluctuation causes the steam to turn into moisture and your glasses will fog up because they are wet.
Unfortunately, warming glasses is no simple task. Using conventional methods, you would need to find a transparent material that can be heated externally, develop a power source for the material, and make sure that the lenses or frames are not in danger of overheating. This is a pretty tall order, especially when you consider that any extra bulk or weight will increase the user’s discomfort.
The ETH Zurich team tackled these engineering challenges by taking a different approach. They developed a special gold coating that uses solar energy to generate heat. It requires no batteries or cables or any other components other than the cladding itself.
The way it works involves placing tiny gold clumps between ultrathin layers of titanium oxide. Gold makes a great conductor of heat, and the titanium oxide layers strengthen the metal’s grip enough to make it perfectly suitable for heating glass and similar surfaces.
The whole thing is only 10 nanometers thick (process size for some microchips) and can be used with other coatings – so it should work for use with transition lenses and car windshields, for example. In fact, the scientists are determined to test the coating on other surfaces such as windows and mirrors.
It will also be interesting to see how this coating can be applied to other optics such as sensors and lasers. The applications of this coating could be endless, especially since scientists insist that it is not as expensive as one might think due to the incredibly small amount of gold required to create the coating.
It is unclear exactly how much heat can be generated using this technique, but Researchers claim it can heat the surface up to 8 degrees Celsius. This is certainly sufficient to protect your lenses from vapor under general conditions. But not enough to generate any usable amount of electricity.
This probably won’t solve the world’s energy crisis, but it certainly has the potential to make life easier for billions of people who wear glasses.