These researchers want to take their butterflies to the bank. They’ve found a way to mimic the nanostructures responsible for giving butterfly wings their colors, and they think butterfly-inspired money designs might hinder counterfeiters.
“We still need to refine our system, but in future we could see structures based on butterflies wings shining from a £10 note or even our passports,” said Mathias Kolle in a university press release. Kolle researched the butterfly’s wing structure with Ullrich Steiner and Jeremy Baumberg at the University of Cambridge.
Butterfly wings don’t use traditional pigment for their flair. Instead, they rely on the way light bounces off tiny multilayer structures on their wings. These micro- and nanostructures come in a variety of shapes (see the “egg carton-like” scanning electron microscope picture below), and scientists have long had inklings as to how different structures result in different colors. But Kolle and colleagues have gone one step further, managing the elusive task of copying this craft.
They studied the swallowtail butterfly (Papilio blumei), and rebuilt the butterfly’s stunning molecular-scaled wing structures. Nature Nanotechnology recently published their findings and a description of their techniques.
Not using pigment may be a way to keep butterflies safe, as the color reflecting from those tiny structures appears differently to different viewers, perhaps camouflage green to predators, but bright blue to mates.
Adopting their techniques could also protect money, if researchers figure out ways to use their wing-mimicing structures to encrypt information in optical signatures. And that means that copying currency would produce a lot more butterflies in counterfeiters’ stomachs.
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Images: Mathias Kolle, University of Cambridge