A team of researchers from the Swiss Federal Institute of Technology (ETH Zurich) has developed a patent-pending ultrathin and 100% transparent coating that is both anti-fogging and defogging.

The 18 nanometer-thick coating, which both removes existing fog on surfaces and prevents its formation, features two layers of titanium oxide surrounding a middle gold layer.

Source: ETH Zurich

According to its developers, the coating uses heat to fight fog, heating itself by selectively absorbing infrared radiation from sunlight.

The new coating does not absorb ultraviolet (UV) rays and visible light from the sun. Instead, selective absorption of the near-infrared portion of the sunlight reportedly heats surfaces up to 8° C, thereby preventing fog.

“We achieve this heating effect by fabricating a metal layer (gold) at a very specific thickness (called the percolation threshold), where an optical anomaly occurs. This leads to a strong and broadband absorption of the near-infrared spectrum over just a few nm (10 nm in total),” the researchers explained.

The researchers are eyeing the affordable and easy to scale coating for future eyeglasses, windows and car windshields.

An article detailing the coating, Transparent sunlight-activated antifogging metamaterials, appears in the journal Nature Nanotechnology.