Nanometer Knitting For Futuristic Clothing

By Roland Piquepaille

Australian and U.S. researchers have found a new way to exploit the old technology of spinning wool. This CSIRO news release, "Futuristic 'smart' yarns on the horizon," tells us that spinning of carbon nanotubes could lead to 'smart' yarns which could be knitted together to make artificial muscles for robot soldiers or even bandages that send a signal after you're hurt. However, this news release is short on facts, and in "Knitting in nanometres," ABC Science Online wrote something more substantial. You'll discover that the scientists "created the yarn by growing a mat of fibres on a substrate, called a nanotube forest." And with this spinning process, this 'forest' can grow as long as you want, like several kilometers long. If it is proven, this is truly amazing, and practical military or medical applications could be ready within five years. Read more...

Before going further, let's look at some very interesting pictures.

Here are several scanning electron microscope (SEM) micrographs showing the structures formed during the process and the multi-walled nanotubes (MWNT) at different magnifications (Credit: Science).

Now, here are the two first paragraphs of the CSIRO news release.

In a collaborative effort, scientists at CSIRO Textile and Fibre Technology (CTFT) have achieved a major technological breakthrough that should soon lead to the production of futuristic strong, light and flexible 'smart' clothing materials.

In partnership with the world-renowned NanoTech Institute at the University of Texas at Dallas, CTFT has adapted textile technologies used to spin wool and other fibres to produce yarns made solely from carbon nanotubes (CNTs).

As you can notice, there is not much 'meat' there. So let's switch to ABC Science Online for more technical details.

Ken Atkinson from CSIRO Textile & Fibre Technology said the nanotubes' structure was similar to a square of hexagonal wire coiled up to form a cylinder.

The researchers created the yarn by growing a mat of fibres on a substrate, called a nanotube forest. A sharp, pointed instrument then pulled at the fibres along the plane of the substrate.

Atkinson said the tubes then formed into a "conga line" and were twisted and wrapped around each other as they were pulled. "As long as there are fibres in the forest, you can make a yarn as long as you want. You get a very even strand," he said.

And Atkinson is pretty vocal about this spinning process -- read carefully this quote.

"People say how can you spin something that is one-third of a millimetre long, but it is the length-to-diameter ratio that matters. We use fibres with a 10 nanometre diameter and put in a lot of wraps."

Atkinson said nanotubes were usually grown to about 300 micrometres. And scientists couldn't make nanotube yarn with continuous lengths without blending the fibres with other materials. With spinning you can get pure nanotube yarn as long you want, Atkinson said.

What can we expect of this 'spinning wool' process adapted to nanotechnology?

Here is what CSIRO says.

Initial research into the potential uses of the new material is focussed on the production of vests and 'soft' body armour to provide protection from bullets and other small ballistic missiles.

"Small ballistic missiles?" Wow! I don't think I need protection against this. ABC gives us more realistic expectations.

The team says its unusually long fibres could also be used to make bandages that help injured limbs move again, tighten to stem bleeding or send a signal to say someone was hurt.

For more information, the research work has been published by the journal Science under the title "Multifunctional Carbon Nanotube Yarns by Downsizing an Ancient Technology." Here are two links to the abstract and to some supporting online material to the article (PDF format, 3 pages). The above illustration was extracted from this document.

Sources: CSIRO news release, November 19, 2004; Heather Catchpole, ABC Science Online, November 19, 2004; Science, Vol. 306, Issue 5700, Pages 1358-1361, November 19, 2004

Related stories can be found in the following categories.

• Chemistry
  
• Military Applications
  
• Nanotechnology
  
• Wearable Technology