July 13, 2024

I, Science

The science magazine of Imperial College

Carbon nanotubes are thinner than a human hair, stronger than steel and incredibly light.

They say diamonds are a girl’s best friend. But depending on how carbon is arranged, you could end up with graphite inside a pencil instead. Rearrange again and you open up the incredible world of carbon nanotubes.

Carbon nanotubes are tiny tubes of graphite, thousands of times thinner than a human hair. They are stronger than steel, conduct heat and electricity better than copper, and are incredibly light.

When first discovered, they were hailed as the future of materials and have found many uses. In medicine carbon nanotubes are cancer detectors, in electronics they are improving batteries, and for the environment they trap polluting oil drops.

But the miracle material lost its momentum. Carbon nanotubes are hard to process, especially in large quantities.

When carbon nanotubes are produced, usually in a powder form, the tubes twist and clump and can’t be used.

Chemicals must be used to coat the tubes, forcing them to separate. But this alters the tubes’ surfaces, reducing their useful effects.

However, scientists at Northwestern University have found the solution – under the kitchen sink.

Cresol is a common chemical found in household cleaners. Cresol detangles the twisted tubes and can simply be washed off without altering the tube structure and without altering the properties.

Using cresol allowed Northwestern University’s Jiaxing Huang and his team to make carbon nanotubes in larger and larger numbers. This lead to new forms of the material being discovered.

In addition to the powdered form normally used, the carbon nanotubes can change into a spreadable paste, a free-standing gel, and a kneadable dough.

“The dough state of nanotubes is fascinating,” said Kevin Chiou, a graduate student in Huang’s laboratory, describing it as “just like playdough.”

One use could be to use the nanotubes as a conductive ink for 3D printing.

But the new forms could revolutionise our day-to-day lives. These new forms act like plastics.

Huang said, “It is really exciting to see… once hard-to-process carbon nanotubes as usable as common plastics.”

Although carbon nanotubes cannot bidodegrade, Dr Adam Clancy, from the Institute for Materials Discovery said that “nanotubes degrade and burn at higher temperatures than most plastics, so they can be recovered… non-damaging processing routes such as cresol will improve the recyclability of these materials.”

The good news goes even further. Cresol is already mass produced and is cheap! “It uses less solvent so is more environmentally friendly”, Dr Clancy said.

If they help us with our plastic problem, carbon nanotubes could end up being our new best friend.

Poppy-Jayne Morgan is studying for an MSc in Science Communication at Imperial College London

Banner image: Carbon Nanotubes, Flickr /Kyla Clay