Can butterflies` wings help cut bank fraud?

Last Updated: Tuesday, June 1, 2010 - 15:15

London: Cambridge scientists have
discovered a way of mimicking the stunningly bright and
beautiful colours found on the wings of tropical butterflies.

The findings could have important applications in the
security printing industry, helping to make bank notes and
credit cards harder to forge.

The striking iridescent colours displayed on beetles,
butterflies and other insects have long fascinated both
physicists and biologists, but mimicking nature`s most
colourful, eye-catching surfaces has proved elusive, a
university release said.

This is partly because rather than relying on
pigments, these colours are produced by light bouncing off
microscopic structures on the insects` wings.

Mathias Kolle, working with Professor Ullrich Steiner
and Professor Jeremy Baumberg of the University of Cambridge,
studied the Indonesian Peacock or Swallowtail butterfly
(Papilio blumei), whose wing scales are composed of intricate,
microscopic structures that resemble the inside of an egg
carton.

Because of their shape and the fact that they are
made up of alternate layers of cuticle and air, these
structures produce intense colours.

Using a combination of nanofabrication procedures -
including self-assembly and atomic layer deposition - Kolle
and his colleagues made structurally identical copies of the
butterfly scales, and these copies produced the same vivid
colours as the butterflies` wings.

According to Kolle: "We have unlocked one of nature`s
secrets and combined this knowledge with state-of-the-art
nanofabrication to mimic the intricate optical designs found
in nature".

"Although nature is better at self-assembly than we
are, we have the advantage that we can use a wider variety of
artificial, custom-made materials to optimise our optical
structures".

As well as helping scientists gain a deeper
understanding of the physics behind these butterflies`
colours, being able to mimic them has promising applications
in security printing.

"These artificial structures could be used to encrypt
information in optical signatures on banknotes or other
valuable items to protect them against forgery.

"We still need to refine our system but in future we
could see structures based on butterflies wings shining from a
10 pound note or even our passports," he says.

Intriguingly, the butterfly may also be using its
colours to encrypt itself - appearing one colour to potential
mates but another colour to predators.

PTI



First Published: Tuesday, June 1, 2010 - 15:15

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