For all those who wear glasses, the fog that forms on the glass is a phenomenon that rots everyday life. Of course, there are already anti-fog liquids, the effectiveness of which is sometimes disputed.
And soon, we can also count on the invention of a group of researchers from the University of ETH Zurich. After several years of work, they succeeded in creating a new coating for glasses, but also for car windshields which prevents humidity from condensing.
Heat glasses using gold
This coating, based on gold, prevents the formation of fogging by warming the lenses with the sun. In fact, it absorbs the sun’s radiation selectively.
In essence, much of the infrared radiation is absorbed, raising the temperature by 8°C. And it is this heating using the sun that prevents fogging.
On the other hand, the coating absorbs only a small part of the radiation on the visible spectrum. And because of this, while using the heat of the sun, the coating remains transparent.
“Traditionally, surfaces are coated with (hydrophilic) water-attracting molecules, which results in an even distribution of condensation. This is how anti-fog sprays work. But the new method instead heats the surface, preventing the formation of moisture-induced condensation”reads a university paper.
The operation of this coating is comparable to anti-fog systems in cars. But instead of generating heat with electricity, the coating uses energy from the sun.
A small amount of gold would suffice
As gold is rare and expensive, you are certainly wondering if this technology, although effective, can be democratized. But according to the researchers, the amount of gold needed is small.
“Gold may be expensive, but researchers point out that coating it requires so little that material costs remain low. The coating comprises tiny, extremely fine clusters of gold sandwiched between two ultra-thin layers of titanium oxide, an electrically insulating material.reads the ETH Zurich post.
These two additional layers increase the effectiveness of the coating and also protect the gold layer from wear. In all, the coating is only 10 nanometers thick.
The technology is already the subject of a patent application. But researchers still want to improve it, by looking for other uses, but also by looking for other materials that could have the same properties.