Important carbon nanotube breakthrough found to have surprising twist

16 May 2018

Image: Rost9/Shutterstock

Trying to mass-produce carbon nanotubes has proven to be incredibly difficult, but a new breakthrough could be about to change that.

The technology of carbon nanotubes sounds like something from science fiction and, while it does exist, it has yet to really escape the confines of the lab.

In fact, excitement into researching the technology has been on the wane after decades of research have failed to accelerate it to where some would want it to be at this stage.

Until now, attempts to mass-produce carbon nanotubes – about 10,000 times thinner than a human hair – have only resulted in powders where the tubes are usually twisted and clumped together.

However, a new breakthrough achieved by a team of researchers from Northwestern University in the US has not only found a way to possibly break this cycle, but also new and weird ways to use carbon nanotubes.

In a paper published to Proceedings of the National Academy of Sciences, the team found a way to mass-produce carbon nanotubes using a common chemical once used in household cleaners.

By using this solvent, called cresol, the team was able to make disperse carbon nanotubes at unprecedentedly high concentrations without the need for additives or harsh chemical reactions to modify the nanotubes.

Carbon nanotube moulds

The carbon nanotube-based dough can be transformed into arbitrary shapes defined by a mould. Image: Jiaxing Huang Group/Northwestern University

‘Nanotubes behave just like polymers’

Then, in a surprising twist, Jiaxing Huang and the team noticed that some weird things were at play, whereby an increase in concentrations of carbon nanotubes pushes them from a dilute dispersion into a thick paste.

As the density keeps on increasing, a free-standing gel is formed before finally becoming a kneadable dough that can be shaped and moulded.

Previous attempts to bypass the clumping problem used chemicals to coat the nanotubes, chemically altering their surfaces to force them to separate. While this did work, the residue left by these chemicals often altered their amazing abilities, such as being more conductive than copper and stronger than steel.

With the newfound ability to mass-produce carbon nanotubes now possible, the research team is equally as fascinated with the amazing side effect of cresol.

“Essentially, this solvent system now makes nanotubes behave just like polymers,” Jiaxing said.

“It is really exciting to see cresol-based solvents make once hard-to-process carbon nanotubes as usable as common plastics.”

Colm Gorey was a senior journalist with Silicon Republic