Certain squids can change their color in a blink of an eye and someday, it seems, humans may be able to do the same. New technology nicknamed “invisibility stickers” could be used to help soldiers camouflage and potentially evade infrared cameras.
How the invisibility stickers work
Led by Gorodetsky, researchers at the University of California at Irvine (UCI) took inspiration from squid skin to develop these camouflage-capable stickers. So how do squids change color? Their skin boasts iridocyte cells, which feature layers of reflectin (a unique protein). Through a biotechnical cascade, the squid can alter the layer’s thickness and spacing. This process impacts how light is reflected on the cells, which in turn affects the skin’s color.
To mimic this behavior, the researchers manipulated bacteria to produce reflectin. They then applied a hard substrate of the reflectin-producing bacteria to the protein. A trigger was crucial for creating changes similar to iridocytes in squids. Acetic acid vapors did the trick, but the research team realized it wouldn’t be practical for soldiers.
"What we were doing was the equivalent of bathing the film in acetic acid vapors -- essentially exposing it to concentrated vinegar," Gorodetsky says.
Eventually, the team was able to develop reflective films on polymer substrates (essentially sticky tape). It can stick to a number of surfaces – including cloth – and alter its appearance by stretching.
“We've developed stickers for use as a thin, flexible layer of camo with the potential to take on a pattern that will better match the soldiers' infrared reflectance to their background and hide them from active infrared visualization," Dr. Alon Gorodetsky said in a statement.
In addition to camouflage purposes, the tape could also be used to trap or release body heat.
Challenges that need to be addressed
According to Gorodetsky, the technology is still far from ready for military use. There are still a number of issues that need to be resolved, including finding out how multiple stickers can respond in sync. Currently, the stickers only identify reflect infrared light. Gorodetsky hopes they could one day work at mid- and far-infrared wavelengths to fool infrared cameras.
However, he envisions the tape as something soldiers could eventually bring with them and use it when the need arises. "We're going after something that's inexpensive and completely disposable," he explained. "You take out this protein-coated tape, you use it quickly to make an appropriate camouflage pattern on the fly, then you take it off and throw it away."
Gorodetsky and his team will present their research at this week’s 249th National Meeting & Exposition of the American Chemical Society (ACS).