Shape shifter
Scientists have created polymer rods that, even after being grossly deformed, will revert toward their original shape when exposed to ultraviolet (UV) light.
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Andreas Lendlein at GKSS Research Center in Teltow, Germany, and his colleagues bestowed this shape-memory property on a polymer blend by adding photosensitive molecules. When exposed to UV light of a certain wavelength, these molecules link, cinching the polymer’s own constituent chains in place. A dose of UV light of a different wavelength cleaves the bonds.