Color-changing coatings ready for the big time

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The dazzling colors of peacock feathers arise from the physical interaction of light with biological nanostructures. Researchers have discovered how to exploit this natural trickery known as structural coloration into a large-scale printing technology that produces lightweight and ultraresistant coatings in any color desirable.

Researchers routinely produce photonic structures to influence the behavior of light for applications such as fiber-optic communications. Many groups have used photonic technology to generate new forms of artificial structural colors that take advantage of the entire spectrum of visible light.

Moving this technology out of the lab is challenging, however, because photonic nanostructures are often fragile and difficult to produce in practical quantities.

Associate Professor Andrea Fratalocchi from the University’s Electrical Engineering program and colleagues from Harvard University and ETH Zurich used wet chemical techniques to help overcome the difficulties of scaling-up photonic colors. Inspired by the nanoporous feathers of the plum-throated cotinga bird, the team’s approach began by sputtering a platinum–aluminum based alloy on to a target surface. Then, a process called dealloying dissolves most of the aluminum and causes the remaining metal to reorganize into a bumpy network featuring open nanopores.

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