Elastic conductors made from carbon nanotubes
By Ben Coxworth
January 26, 2012
Whether it's touch-sensitive skin for robots, clothing made from smart fabrics, or devices with bendable displays, stretchable electronics will be playing a large role in a number of emerging technologies. While the field is still very new, stretchable electronic devices may have come a step closer to common use, thanks to research being conducted at North Carolina State University. Scientists there have recently developed a new method for creating elastic conductors, using carbon nanotubes.
A team led by Dr. Yong Zhu started by using a transfer printing process to place aligned carbon nanotubes on an elastic substrate. When that substrate was stretched, the nanotubes separated from one another, but maintained their parallel alignment. Once the substrate was relaxed, however, the nanotubes didn't return to their original configuration. Instead, they buckled, forming a pattern that looked like squiggly lines drawn onto a flat surface.
The buckled nanotubes were subsequently able to conduct electricity, in both relaxed and stretched states.
The researchers believe that their process should make the manufacturing process of stretchable electronics more efficient, as the substrate won't need to be stretched for the conductors to be applied. Should there be situations where application on a relaxed material isn't the best way to go, however, Zhu has also demonstrated a technique for applying the carbon nanotubes to an elastic substrate while it is stretched - in this case, instead of squiggly lines, the nanotubes form into accordion-like ribbons when the material is relaxed.