August 31

(PHYS.ORG)  This is a photograph of the world’s first transparent speaker “…consisting of a thin sheet of rubber sandwiched between two layers of a saltwater gel, and it’s as clear as a window. A high-voltage signal that runs across the surfaces and through the layers forces the rubber to rapidly contract and vibrate, producing sounds that span the entire audible spectrum, 20 hertz to 20 kilohertz. But this is not an electronic device, nor has it ever been seen before.

Published in the August 30 issue of Science, it represents the first demonstration that electrical charges carried by ions, rather than electrons, can be put to meaningful use in fast-moving, high-voltage devices. Ionic conductors can be stretched to many times their normal area without an increase in resistivity — a problem common in stretchable electronic devices. Secondly, they can be transparent, making them well suited for optical applications. Thirdly, the gels used as electrolytes are biocompatible, so it would be relatively easy to incorporate ionic devices—such as artificial muscles or skin—into biological systems. After all, signals carried by charged ions are the electricity of the human body, allowing neurons to share knowledge and spurring the heart to beat. Bioengineers would dearly love to mesh artificial organs and limbs with that system.”

For the full article, click here.  Photo courtesy Christoph Keplinger and Jeong-Yun Sun, Whitesides and Suo Research Groups, Harvard University

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