A new artificial skin can change color when exposed to light and could be used in applications, such as active camouflage and large-scale dynamic displays, reported the German news agency.
The material, developed by researchers from the University of Cambridge, is made of tiny particles of gold coated in a polymer shell and then squeezed into micro-droplets of water in oil.
When exposed to heat or light, the particles stick together, changing the color of the material, according to the results that were reported in the journal Advanced Optical Materials.
Animals, such as chameleons and cuttlefish, are able to change color thanks to coloring materials found in skin cells with contractile fibers that move pigments around. The pigments are spread out to change the color, or pull it out from the skin to regain its natural color.
The artificial method developed by the Cambridge researchers is built on the same principle, but instead of contractile fibers, they used light-powered nano-mechanisms.
The Science Daily website reported that when the material is heated above 32C, the nano-particles store large amounts of elastic energy in a fraction of a second, as the polymer coatings expel all the water and collapse. This has the effect of forcing the nano-particles, and thus, changes the color of the skin.
When the material is cooled, the polymers take on water and expand, and the gold nano-particles are strongly and quickly pushed apart, so the skin regains its natural color.
The website quoted Andrew Salmon from Cambridge's Cavendish Laboratory, saying: "Loading the nano-particles into the micro-droplets allows us to control the shape and size of the clusters, giving us dramatic color changes."
