Hasta La Gadget!

We’ve featured a sound system called the Transparent Speaker, which really only has a glass case. Two post-doctoral fellows at the Harvard School of Engineering and Applied Sciences (SEAS) made an actual transparent speaker. It’s stretchable too. But the loudspeaker is not an electronic device; it’s an ionic device.

Instead of electrons, Jeong-Yun Sun and Christoph Keplinger’s speaker uses ions in an electrolyte to transport electric charge. The speaker is made of a thin and transparent sheet of rubber sandwiched between two layers of polyacrylamide gel filled with saltwater. When a high-voltage current is passed through these layers, the rubber sheet acts as a diaphragm. Harvard SEAS reports that this clear device can produce any sound in the “entire audible spectrum”, from 20Hz to 20KHz.

The speaker demonstrates two of the key advantages of an ionic device over an electronic device – transparency and elasticity – but there’s a third benefit: biocompatibility. Ionic devices are easier to incorporate into living creatures compared to electronics. They may also be used to create what Keplinger calls soft machines: “Engineered ionic systems can achieve a lot of functions that our body has: they can sense, they can conduct a signal, and they can actuate movement. We’re really approaching the type of soft machine that biology has to offer.”  

With that kind of potential, it’s not surprising that there have been previous efforts to make ionic conductors for practical use. Harvard SEAS explained that ionic conductors are prone to undergoing chemical reactions – including, uhm, combustion – when exposed to high voltage, and that ions move slower through a circuit compared to electrons due to their size and weight. Fortunately, Sun and Keplinger’s ionic conductor “overcomes both of these problems.” You can read the full report on Harvard SEAS’ website.

[via The Verge]

IBM is worried that we’re reaching the end of the road for CMOS technology — that we need new materials beyond silicon to keep the power draw down in chips as their performance goes up. It may keep future circuitry extra-lean through a new technique that puts a metal oxide in silicon’s place and allows for non-volatile processors and memory. By running ionized liquid electrolytes in currents through the oxide, the company can switch that oxide from an insulator to a conductor (and vice versa) that can reliably maintain its state, even when there’s no power. The trick would let a logic gate or switch kick into action only when there’s an event, rather than needing constant jolts of electricity — and without the pressure or temperature changes that had ruled out metal oxides for chips in the past. We’re still far from replacing silicon with more efficient oxides given the early state of IBM’s work, but having a consistent method is an important first step.

Filed under: Science, Alt

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Source: IBM