Materials

Study suggests moth-inspired wallpaper could one day soundproof homes

Study suggests moth-inspired w...
The sound-absorbing scales used in the study were obtained from Chinese oak silk moths
The sound-absorbing scales used in the study were obtained from Chinese oak silk moths
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The sound-absorbing scales used in the study were obtained from Chinese oak silk moths
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The sound-absorbing scales used in the study were obtained from Chinese oak silk moths
A microscope image of one of the wing scales
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A microscope image of one of the wing scales
A microscope image shows the sound-absorbing structure of one of the wing scales
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A microscope image shows the sound-absorbing structure of one of the wing scales
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Two years ago, scientists at the University of Bristol discovered that certain types of moths evade bats via sound-absorbing scales on their body. New research now suggests that wallpaper inspired by those scales could be used to block out unwanted noises.

Bats locate moths in the dark by emitting ultrasonic calls that reflect off the insects' bodies. Some moths are able to hear those calls, and take evasive action accordingly. The 2020 study focused on other types of moths that are deaf, and therefore unable to hear the bats' calls.

It was found that those moths had instead evolved special scales on their wings and thorax, which absorb up to 85 percent of incoming sound energy. As a result, the echolocation calls are poorly reflected, making it difficult for bats to find the moths.

At the time, the scientists wondered how effective the scales' sound-absorbing characteristics might be at blocking noises other than bat calls. The new U Bristol study explored that question further.

A microscope image shows the sound-absorbing structure of one of the wing scales
A microscope image shows the sound-absorbing structure of one of the wing scales

A team of researchers started by cutting 8-mm discs out of the wings of euthanized deaf Chinese oak silk moths (Antheraea pernyi), then placing those sections on same-sized aluminum discs. When a speaker pointed at the discs emitted ultrasound signals, the wing tissue was found to absorb as much as 87 percent of the sound energy – and it did so over a wide range of frequencies and angles.

What's more, the material accomplished this feat even though it was very thin. In fact, the layer of scales was just one fiftieth the thickness of the wavelength of the sound it was absorbing.

It should be noted that the ultrasound signals used in the study were above the range that can be heard by humans. The scientists are confident that a manmade version of the wing scales could be adapted to work against noises that we can hear, however, and they now hope to develop such a material.

"Moths are going to inspire the next generation of sound-absorbing materials," said the lead scientist, Prof. Marc Holeried. "One day it will be possible to adorn the walls of your house with ultrathin sound absorbing wallpaper, using a design that copies the mechanisms that gives moths stealth acoustic camouflage."

The research is described in a paper that was recently published in the journal Proceedings of the Royal Society A.

Source: University of Bristol

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4 comments
4 comments
Brian M
This experiment appears to be about not reflecting sound back to the bat (important for the moth). For sound control in buildings reflection is fairly easy and cheap to do compared to sound proofing which is stopping the transmission of sound, which is difficult especial at the lower frequencies requiring heavy masses and insulating materials and techniques.
michael_dowling
Good idea,but it might present problems with keeping it clean without damaging it.
claudio
Wallpaper is no longer used in many countries. Any other application?
mediabeing
Bullspit!
Let's see synthetic whatever it is keep high energy low frequency stuff out.
That's the stuff that really irritates, the stuff from sub-woofers. Let's see Mr. Moth take care of that.