Researchers at the Massachusetts Institute of Technology stumbled onto what one called a “very radical” discovery — the new material they had created, akin to silk, could function much in the way a wall does, only at a fraction of the thickness.
The researchers first set out to create a fiber, made up of silk, canvas and other common materials, that could act as a microphone and amplify sound. But, as their work took shape they realized the fiber could do the opposite as well — create quiet.
The silk is barely thicker than human hair and is made by heating the materials and drawing them into a fiber. Since each material flows at the same temperature, they can be pulled into a fiber while maintaining their structure.
Yoel Fink, a professor of Materials Science and Engineering at MIT told MassLive fibers are “ubiquitous” in human life, and have been for centuries. But, he said, most fibers “pretty much do the same thing” and “none of them are technologically advanced.”
So, Fink and other researchers at MIT sought to change that, beginning by combining multiple materials into a fiber, much in the way that almost everything we interact with on a daily basis is made up of more than one material. Fink noted that your smartphone, for example, is a combination of metals and glass.
The sound-suppression work published recently in the journal “Advanced Materials” builds on initial efforts by the same group of researchers to create what Fink described as a hyper-sensitive microphone. Creating the microphone was a far simpler task than finding a way to create a way to block out sound, Fink told MassLive.
“Creating silence, that’s a lot of work,” Fink said. “The question was, could you take a very thin fabric and make it behave as if there was a thick wall there?”
The fabric can suppress sound by generating sound waves that interfere with an unwanted noise to cancel it out (as seen in figure C) or by being held still to suppress vibrations that are key to the transmission of sound (as seen in figure D). (Image: Courtesy of the researchers)Image: Courtesy of the researchers
Ultimately researchers found that they could effectively block out sound in two ways — first by applying voltage to the fabric that causes it to vibrate, creating sound waves that effectively block out noise, much in the way that noise-canceling headphones work. The other, perhaps more surprising approach, involved keeping the fabric perfectly still to suppress vibrations that transmit sound.
The “very radical” application for the new material would be replacing walls altogether with a material akin to silk pajamas, Fink said.
Noise is a “very ubiquitous” problem, he added.
“That’s what made this work. We were very excited about it,” he told MassLive.
But for now, the applications for the material remain largely theoretical.
While the material has exciting possible applications in the real world, Fink said it would have to shift from the research phase to actually becoming a product, and the commercial interest in such a thing is not certain.
“This is just too new, I don’t even know what the market is,” he said. “We’re not yet at a point where I could give you what the killer application is going to be.”
The researchers — Fink included — are very much open to ideas for how exactly the material might be applied, be it on a plane, in a hospital, or somewhere else entirely.
“We haven’t figured it out, it’s still ahead of us,” he said.
