The remarkable speaker is made up of a thin rubber sheet squeezed between layers of saltwater gel. A high-voltage signal runs through the layers, forcing the rubber to contract and vibrate rapidly, producing sounds that range from 20 hertz to 20 kilohertz.
The study, published in the journal Science, was co-led by Jeong-Yun Sun, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences. According to Sun, ionic conductors could be set to replace certain electronic systems, offering several advantages. Ionic conductors can be stretched beyond their normal area without an increase in resistivity. As well, the electrolyte gels are biocompatible, making it relatively easy to incorporate such devices into biological systems.
This isn’t a foreign concept for the human body. Charged ion signals are the so-called electricity of our system. It’s no surprise that bioengineers would be interested in meshing artificial organs and limbs with that system. According co-author Christoph Keplinger, the ultimate vision is soft machines, in which engineered ionic systems achieve many of our bodily functions.