Carbon Nanotubes Bend and Stretch and Still Conduct

It seems the most desirable characteristic for electronics at the moment is flexibility, at least as far as nanotechnology research is concerned. Somehow—and I am not sure why—being able to bend electronic devices into various shapes seemed to take hold as a much sought-after quality with Nokia's conceptual introduction of the Morph phone four years ago based on joint research with Cambridge University.

I for one have always felt that a longer lasting battery was a more attractive feature in a phone than being able to wrap it around my wrist. But artificial skin has been raised as a possible application for flexible electronics recently and that sounds a good deal more like market pull than technology push.

Whatever the future holds for flexible electronics, the one thing we can say for certain is that nanotechnology, specifically carbon nanotubes, are pretty good at enabling it.

The most recent research in this vein comes from researchers at North Carolina State University who have developed a method for using carbon nanotubes as elastic conductors.

"We're optimistic that this new approach could lead to large-scale production of stretchable conductors, which would then expedite research and development of elastic electronic devices," says Dr. Yong Zhu, an assistant professor of mechanical and aerospace engineering at NC State, and lead author of a paper describing the new technique.

The approach, which was published online Jan. 23 in Advanced Materials, involves placing carbon nanotubes in parallel lines onto an elastic substrate. When the substrate material is stretched, the nanotubes are separated and maintain their parallel alignment. When the substrate is relaxed, the carbon nanotubes do not fall back into their previous positions but instead form into squiggly shapes and are now elastic and flexible while still retaining their excellent electrical properties.

The proposed list of applications includes “implantable medical devices, and sensors that can be stretched over unmanned aerial vehicles.” A bit of a new twist for flexible electronics.

Is this a quality of carbon nanotubes that simply works or is it truly useful? We’ll see if industry comes knocking.



IEEE Spectrum’s nanotechnology blog, featuring news and analysis about the development, applications, and future of science and technology at the nanoscale.

Dexter Johnson
Madrid, Spain
Rachel Courtland
Associate Editor, IEEE Spectrum
New York, NY