Wednesday, March 11, 2020

Ultra-black butterflies may inspire future 'blackest-black' materials

Amanda Kooser


It may be time to ditch the Spinal Tap jokes and start dropping Iron Butterfly references when it comes to talking about the world's blackest-black materials.

© Provided by CNET "The black patches on the wings of some butterflies are 10 to 100 times darker than everyday black objects," said Duke University. Richard Stickney, Museum of Life and Science

Duke University doctoral student Alex Davis conducted a study on ultra-dark butterflies that could lead to new innovations in super-dark coatings. These coatings, the most famous of which is known as Vantablack, are used for everything from telescopes to art projects.

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But ultra-black butterflies like Rajah Brooke's birdwing butterfly give human-made coatings like Vantablack some serious competition. "As little as 0.06% of the light that hits them is reflected back to the eye," Duke said in a release on Tuesday.

What makes this phenomenon so intriguing is the light weight and thinness of the butterflies' natural coloration. Davis and colleagues used an electron microscope to take a super-close-up look at how the insects achieve this feat.

Zooming in on a butterfly wing reveals layers of scales. As for the ultra-black appearance, Duke described it as "an optical illusion created by the 3D structure of the butterflies' wing scales."

Microscope images highlight the details of these nanostructures, which appear as a series of ridges with honeycomb-like formations in between. The researchers discovered these "ridges and pillars are deeper and thicker in ultra-black scales compared to 'normal' black scales." 
© Provided by CNET A scanning electron microscope shows the structures of the wing scales of the Rajah Brooke's birdwing butterfly at three different levels of magnification. Alex Davis, Duke University

The butterfly scales aren't as black as Vantablack or similar coatings, but the paper noted they are thinner and can be fabricated at lower temperatures. The study calls for further research into the viability of turning this biological wonder into a synthetic material.
© Richard Stickney, Museum of Life and Science

The butterflies scrutinized in the study use black as a key part of their wing color schemes. Bright patches ranging from blue to green to red pop out against the ultra-dark backgrounds.

While scientists are fascinated by the potential for these nanostructures, the butterflies themselves might just be looking for a good time. "We think it's likely some sort of signal to mates or maybe a predator. But there's a host of other possibilities, and we're hoping to clear that up," said Davis.

Vantablack swallows everything it's painted on




 

a close up of a box: Surrey NanoSystems in the UK announced Vantablack, a nanotech material, in 2014 to much fanfare and many Spinal Tap jokes. It became known as one of the blackest-black materials ever created.At the time, Surrey NanoSystems described Vantablack as "revolutionary in its ability to be applied to lightweight, temperature-sensitive structures such as aluminium whilst absorbing 99.96% of incident radiation, believed to be the highest-ever recorded." None more black. Surrey has continued to refine Vantablack and even figured out how to make the light-absorbing coating work as a spray. It has since graced everything from wristwatch faces to high-end vehicles.
16 SLIDES © Provided by CNET

a glass of wine: Believe it or not, these are two of the same sculpture of a man's head. The one on the left is painted with a spray-on version of Vantablack, making it harder to make out its 3D features.
This sideways view of the Vantablack-painted face sculpture shows how the sculpture appears to be almost 2D from any angle you view it at.


If you're bummed about not being able to order Vantablack paint for your own projects, there is a decent alternative: Black 3.0 from Culture Hustle. The company describes the product as the "blackest and mattest acrylic paint on the planet." It can be applied with a brush and still absorbs up to 99% of visible light. It's not Vantablack, but it's amazing in its own right.

Surrey NanoSystems in the UK announced Vantablack, a nanotech material, in 2014 to much fanfare and many Spinal Tap jokes. It became known as one of the blackest-black materials ever created.At the time, Surrey NanoSystems described Vantablack as "revolutionary in its ability to be applied to lightweight, temperature-sensitive structures such as aluminium whilst absorbing 99.96% of incident radiation, believed to be the highest-ever recorded." None more black. Surrey has continued to refine Vantablack and even figured out how to make the light-absorbing coating work as a spray. It has since graced everything from wristwatch faces to high-end vehicles.

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