Vanishing Act: Scientists Develop Device That Disappears on Command

This is a screen shot of a new polymer, developed by researchers at the Georgia Institute of Technology, that disappears when exposed to sunlight. The substance was developed for the U.S. Department of Defense but has non-military applications as well. (American Chemical Society via YouTube)

(CN) – With all the makings of science-fiction fantasy come to life, scientists at the national meeting of the American Chemical Society revealed Monday a new polymer to be used in military missions that vaporizes and melts away with the click of a button or from exposure to sunlight.

Unlike biodegradable plastic which slowly degrades over a year, the new polymer disappears instantly, making it the perfect material for parachutes or rigid-winged gliders used to ferry airborne packages hundreds of miles across hostile territory. The material can vaporize upon the completion of a military mission or through exposure to sunlight, leaving no trace so as to avoid detection and alleviate the need for device recovery, according to the American Chemical Society.

The polymer was developed for the Department of Defense by Paul Kohl and researchers at the Georgia Institute of Technology.

Kohl said at a press conference Monday the polymer is made of the chemical phthalaldehyde, a readily-available chemical made in large quantities for use in antibacterial wipes.

“It is safe; however, like all chemicals, one has to be careful in use of it,” Kohl said Monday.

“You certainly would not want to eat or drink this. It has a chemical odor like most organic chemicals,” he added.

The technology has already been incorporated in military devices by other researchers. It could also be used in non-military applications, with researchers developing a disappearing epoxy to be used as a temporary adhesive in building materials.

Other applications include disappearing sensors for environmental monitoring, leaving no trace behind once the sensors are finished collecting data, according to the American Chemical Society.

Kohl said Monday while the phthalaldehyde disappears completely, plasticizer chemicals added to the polymer to make it “brittle and hard” in the case of the rigid-wing glider, or “soft and flexible” for use in parachutes will seep into the ground and leave an oily or wet stain that eventually disappears “into relatively nontoxic things” from exposure to the elements.

In order to disappear or break apart, polymers’ “ceiling temperature” must typically be below the ambient temperature. Common polymers have a ceiling temperature above ambient temperature and even when they are warmed remain stable, with some of the materials take a long time to decompose.

For the common polymer polystyrene to decompose, for example, the thousands of chemical bonds linking the monomers together in the material must all be broken.

In the case of the latest polymer developed by Kohl, it’s a low-ceiling temperature polymer, so once one bond breaks, it creates a domino-effect where all the other bonds quickly fall apart, causing the material to vanish.

Researchers attempted for years to make self-destructing polymers but were unsuccessful because of the material’s instability at room temperature. But Kohl and his research team at the Georgia Institute of Technology made a breakthrough by removing all impurities formed during the synthesis. Once they optimized the polymer’s synthesis, they were able to develop how to make it disappear, according to the American Chemical Society.

The researchers initially incorporated a photosensitive additive into the polymer which absorbs light and catalyzes depolymerization.

“Initially, we made it photosensitive to just ultraviolet light so we could make the parts in a well-lit room with fluorescent lighting, and it was just fine; it was stable,” Kohl said in a statement.

But once the polymer was exposed to sunlight, it vaporized quickly, sending the scientists back to the drawing board to figure out how to stall depolymerization.

Kohl said researchers would keep the polymer in a dark room until it was ready to be used, then would deploy it during the day with up to three hours before it decomposes.

The technology is customizable, Kohl said Monday, with researchers having the option to change the UV wavelength and dose needed to trigger the polymer’s disappearance based on conditions such as altitude.

Researchers are also considering other methods to start the decomposition process, including possible chemical methods.

Click here to see the disappearing polymer in action.

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