Scientists have invented a solution to one of the most frequent problems faced by those who wear glasses. Researchers at the Federal Institute of Technology Zurich (ETH) developed a coating that would prevent glasses from fogging up, even when you wear a mask. The coating, based on gold nanoparticles, could also be used on car windshields or camera lenses.
The nanocoating absorbs solar radiation and heats the surface, preventing condensation from forming that fogs up the glasses. This is possible thanks to a thin layer made up of tiny gold particles evenly distributed. The cape is coated on both sides with titanium oxide, an electrically insulating material that works as a shield to prevent wear.
Both enhance the efficiency of surface heating, which can increase up to eight degrees Celsius. The sandwich results in a transparent and flexible coating, with a thickness of only 10 nanometers. The researchers mention that due to its properties it is more efficient, since absorbs infrared light more selectively.
The proposal by the ETH team of scientists departs from conventional methods that use molecules that attract water to distribute condensation. The gold-based coating passively heats the surface of your glasses thanks to sunlight. Curiously, this virtue also becomes its main drawback, since it only works during the day.
Fog-free glasses, although only during the day
The new anti-fogging coating is the fruit of several years of work on passively heated coatings. The ETH scientists announced a gold-based coating three years ago, which had the same properties. The difference with that version is that the current job it is noticeably thinner —twelve times thinner than conventional gold leaf — and is flexible, so can be applied to curved surfaces like glasses.
Normally it’s dark surfaces that absorb light and convert it to heat, but we’ve created a transparent surface that has the same effect.
Efstratios Mitridis, ETH researcher
Because sunlight is their energy source, the researchers are working on alternatives to make it work smoothly at night. One of them is to insert a small battery into the frame of your glasses. With it, the conductive property of gold would be used by emitting small discharges that would serve to heat the surface.
Similarly, those responsible for the study explore other materials with similar properties. Although the amount of gold used in the layer is minimal and does not represent a considerable expense, the demand for this precious metal in many industries forces the search for alternatives. The idea is that the implementation cost is so low that it can be mass-produced.
Dimos Poulikakos and Thomas Schutzius, ETH professors in charge of the research group, noted that the nanocoating uses conventional manufacturing methods. Their goal now is to further refine the product to ensure its durability, while also working with a partner who can produce it at an industrial level.
If they do, they will have solved one of the problems that those who wear glasses face, one that even soap remedies or anti-fog sprays have not been able to solve.