MIT scientists orchestrated the development of new fibers that is capable to detect and produce sound, and proclaim that could be used to produce clothes that act as microphones.
The concepts of the latest acoustic fibers are based on a plastic often used in microphones. Through experimenting with the plastic’s fluorine content, researchers guarantee that its molecules remained lopsided — with fluorine atoms organized on one side and hydrogen atoms on the other — creating a piezoelectric effect that survives the heating and drawing process.
In the standard piezoelectric microphone, the electric field is produced by metal electrodes. But in a fiber microphone, the drawing process would cause metal electrodes to lose their shape. So the researchers instead used a conducting plastic that contains graphite.
“You can actually hear them, these fibers,” says Noémie Chocat, a graduate student in the materials science department. “If you connected them to a power supply and applied a sinusoidal current, then it would vibrate. And if you make it vibrate at audible frequencies and put it close to your ear, you could actually hear different notes or sounds coming out of it.”
In addition to biological sensors and wearable microphones, another feature application of the fibers could include loose nets that efficiently monitor water flow in the ocean and large-area sonar imaging systems with much higher resolutions – fabric woven from acoustic fibers would provide the equivalent of millions of tiny acoustic sensors.
Zheng Wang, a research scientist in MIT’s Research Lab of Electronics, indicated that the same mechanism that allows piezoelectric devices to convert electricity into motion could also work in reverse. “Imagine a thread that can generate electricity when stretched,” he says.
Finally, however, researchers still hoping to successfully amalgamate the properties of their experimental fibers in a single fiber. Strong vibrations, for instance, could vary the optical properties of a reflecting fiber, enabling fabrics to communicate optically.