Volume 95 Issue 35 | p. 11 | News of The Week
Issue Date: September 4, 2017

Coiled nanotube yarn generates electricity when stretched

Scientists have developed “twistrons” that harvest electrical energy from motion
Department: Science & Technology
News Channels: Nano SCENE, Materials SCENE
Keywords: Electronic materials, carbon nanotube yarn, twistron
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This scanning electron microscopy image shows a tightly coiled carbon nanotube yarn that can generate electricity when stretched or twisted.
Credit: University of Texas, Dallas
Scanning electron photomicrograph of tightly coiled carbon nanotube.
 
This scanning electron microscopy image shows a tightly coiled carbon nanotube yarn that can generate electricity when stretched or twisted.
Credit: University of Texas, Dallas
Stretching a tightly coiled carbon nanotube yarn in an electrolyte bath generates enough electricity to power a light-emitting diode (right).
Credit: Science
Stretching a tightly coiled carbon nanotube yarn in an electrolyte bath generates enough electricity to power a light-emitting diode (right).
Credit: Science

A new material could help harvest the energy from ocean waves or even human movement. The material, a carbon nanotube yarn, generates electricity when stretched or twisted.

An international team, led by Seon Jeong Kim of Hanyang University and Ray H. Baughman of the University of Texas, Dallas, made the materials by twisting multiwalled carbon nanotube yarns until they became tightly coiled. Stretching decreases the ability of the yarn to store electrical charge, which increases its voltage, leading to an electrical current (Science 2017, DOI: 10.1126/science.aam8771).

The scientists also coated the yarns with a gel electrolyte and then interwove the fibers with fabric in a shirt, allowing the researchers to monitor a person’s breathing from the current generated as the person’s chest expanded and contracted. According to Baughman, the team’s “twistrons” generate more than 100 times as much power as similar electricity-generating materials that can be woven into fabric. The twistrons provide enough power to transmit up to 2 kilobytes of data over 100 meters every 10 seconds.

To harvest electricity from near-shore ocean waves, the research team suspended a 10-cm-long twistron weighing only 1 mg between a weight and a balloon in the Gyeongpo Sea, just off the coast of South Korea. The weight anchored one end to the seafloor, and each passing wave pulled the balloon, stretching the coiled nanotube, generating an average of about 2 µW of power.

Large-scale harvesting of ocean wave energy would be limited by the manufacturing cost of these nanotube yarns, however. An important next step “is to take what we’ve learned from these carbon nanotube harvesters and apply it to less expensive materials that are commercially available,” Baughman says.

John A. Rogers, of Northwestern University, calls the twistron technology “a clever type of platform” and adds that it provides a variety of technological opportunities, particularly for powering biomedical monitoring devices.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society
Comments
Steve Ritter (Thu Sep 07 10:15:17 EDT 2017)
Andrew Roxburgh McGhie, a UPenn polymer chemist with a penchant for writing poems about C&EN content, has contributed this yarn for his friend Ray Baughman:

A Tall Yarn
This tall yarn it may be the best
At perking up industrial interest
For carbon nanotube yarn can be taken
And tightly coiled till it's almost breakin’
When a ten centimeter length of this ‘twistron’
Was suspended between a weight and a balloon
Then place in the sea, all did rave
For two microwatts was generated per wave
As it stretched and relaxed with such felicity
This one milligram sample generated electricity
It was S. Kim and R. Baughman at U.T. Dallas
Who made this discovery that did enthrall us
So to them and their team let's tip our hat
For expanding work on their carbon nanotube mat
Where will it lead us? No one can predict
But the world is their oyster, which none can restrict

Jim Parsons  (Sun Sep 10 15:48:51 EDT 2017)
How cool is this? Really like this finding. A series of windmills with an eccentric for each pulling or tugging on a rope of twine of this stuff? Combined with rechargeable batteries might go a long way to reduce CO2? Not to mention provide power to out of the way spots on the planet.
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