Gel-based Audio Speaker

two major advantages of ionic conductors are that they can be very stretchy and completely transparent, two properties difficult to achieve with electronics

So now we are going to a soft machines era? This is an ionic speaker, 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 without the need of lot of power. High voltages can set off electrochemical reactions in ionic materials, producing gases and burning up the materials. Ions are also much larger and heavier than electrons, so physically moving them through a circuit is typically slow. The system invented at Harvard overcomes both of these problems, opening up a vast number of potential applications including not just biomedical devices, but also fast-moving robotics and adaptive optics. Stretched, transparent and biocompatible. You could also place this speaker on a window and achieve active noise cancellation - complete silence inside.



To make the speaker, a membrane of transparent, insulating rubber is sandwiched between two layers of transparent, conductive gel. The electrical connection to the power source is established outside of the active region of the device, where it does not need to be transparent. The Harvard team responsible for this research will now focus on the best combinations of ionic conductive materials for compatibility, long life and adhesion between the layers.

This research was supported by the National Science Foundation through a grant to the Materials Research Science and Engineering Center at Harvard University (DMR-0820484) and by the Army Research Office (W911NF-09-1-0476). It was also enabled in part by the Department of Energy (ER45852) and the Agency for Science, Technology, and Research (A*STAR), Singapore.

[via harvard]