Date: 29/01/2012

Electronic device buit-in into a shirt is possibe due to elastic conductors

To makes the electronic devices physically-flexible, researchers at North Carolina State University have developed a new method for creating elastic conductors made of carbon nanotubes.

"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 potential applications include devices that can be incorporated into clothing, implantable medical devices, and sensors that can be stretched over unmanned aerial vehicles.

The conductive materials is made elastic by buckling them. Zhu's new method buckles carbon nanotubes on the plane of the substrate. Think of the nanotubes as forming squiggly lines on a piece of paper, rather than an accordion shape that zigs up and down with only the bottom parts touching the sheet of paper, stated the the release.

Carbon nanotubes is selected for their sturdy, stable, and excellent conduction properties and can be aligned into ribbons.

Aligned carbon nanotubes are placed on an elastic substrate using a transfer printing process. The substrate is then stretched, which separates the nanotubes while maintaining their parallel alignment.

When the substrate is relaxed, the nanotubes buckle - creating what looks like a collection of parallel squiggly lines on a flat surface.

A paper describing the new approach, "Buckling of Aligned Carbon Nanotubes as Stretchable Conductors: A New Manufacturing Strategy," was published online Jan. 23 in Advanced Materials. The paper was co-authored by Feng Xu, a Ph.D. student at NC State.