Superstrong Artificial Muscles and More From New Nanotube Material

Sheets of carbon nanotubes could make strong, stretchy artificial muscles with amazing properties

3 min read

19 March 2009—A revolutionary new material, light as air yet stronger than steel, could be used to make artificial muscles for robotic explorers operating on the broiling plains of Venus or the ice sheets of Europa, scientists say. The material could also be used for more down-to-earth applications, such as improving solar cells or organic LED displays, powering industrial robots, or reinforcing airplane fuselages.

The material, described in the 20 March issue of Science, is an aerogel—a porous, low-density solid—made from carbon nanotubes, and it has an eye-popping list of special properties. Its density is approximately 1.5 milligrams per cubic centimeter, only slightly denser than air. In one direction (along the axis of the tubes), it’s stiffer than steel. But when a voltage is applied across the aerogel [see video], repulsive forces between the nanotubes rapidly triple the material’s width, causing it to expand at 37 000 percent per second. That’s 10 times as far and 1000 times as fast as natural muscle can move, and the material does so while generating 30 times as much force as a natural muscle.

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3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

10 min read
An image of stacked squares with yellow flat bars through them.
Emily Cooper
Green

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.

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