This Simple Black Film Made From Carbon Nanotubes Is Stronger Than Kevlar

This Simple Black Film Made From Carbon Nanotubes Is Stronger Than Kevlar

This looks like the kind of thin material you might make a trash bag out of. But that would be a waste because this material, made from carbon nanotubes, is stronger and more compliant then kevlar or carbon fibre.

Carbon nanotubes have been an exciting prospect in material science for years now: At the microscopic level, they're super strong and stretchy. But when you make a bulk material out of them, their properties are watered down because they become randomly arranged -- and they need to lie in parallel to make the most of their strength. Now, a team of researchers from the East China University of Science & Technology have developed a way to create films where nanotubes are neatly aligned.

They use a technique which Chemical and Engineering News likens to glass blowing. Essentially the team uses a stream of nitrogen gas to push a layer of carbon nanotubes along the surface of tube in a furnace held at around 2,100°F. As it exits, the tubular nanotube material is wound around drum, flattening and cooling into two-layer film. The team can then compress the film by applying pressure using a system of rollers.

It may sound oddly low-tech, but the results are impressive. The film has an average tensile strength of 9.6 gigapascals. For context, kevlar fibres have a strength of about 3.7 gigapascals and carbon fibre around 7 gigapascals. It's also relatively stretchy: it can extend by 8 per cent, which is rather more than the 2 per cent that carbon fibre can image. The properties can be exploited in multiple directions by adding layers on top of each other in different orientations.

It's thought that the new film could be used to create strong, perhaps even structural, coatings for vehicles or aerospace parts, or new kinds of armour for military applications. Or very, very good trash bags.

[NanoLetters via C&EN via Engadget]