A Chinese research team have found new approaches to pull carbon nanotubes into continuous yarns up to 30 centimetres long - an achievement that may facilitate mankind's manipulation of matter atom by atom in the future.

 

The breakthrough was made by Jiang Kaili and his colleagues at Beijing-based Tsinghua University in May, the latest issue of science magazine Nature stated.

Jiang described the carbon nanotube yarns as thin ribbons composed of parallel threads that have diameters in the range of several hundred nanometres, with the width of the yarn roughly depending on the number of threads in it.

A nanometre represents 1 billionth of a metre.

Scientists have found matter demonstrates physical properties unlike the arenas of basic particles like atoms and the macro arena pertaining to our ordinary world.

By studying these phenomena, scientists hope to produce machinery to manipulate matter atom by atom.

However, manipulation of matter within nano-scale space has proved extremely difficult, yet critical for any serious applications in the future.

Carbon nanotubes, or CNTs, have attracted scientists in this field because of their excellent strength and resilience. Preparation and manipulation of CNTs has been one of the most challenging yet thriving research fields.

The findings should translate the remarkable mechanical and electrical properties of CNTs to a macroscopic scale, the article noted.

The work of Jiang and his team at the Department of Physics and Tsinghua-Faxconn Nanotechnology Research Centre was described by the magazine as "impressive and creative."

Jiang and his team's discovery could lead to longer nanotube fibres (metres, kilometres...wound up on to a roller) to be made with nanotubes grown on a large substrate, the magazine stated.

Jiang's team obtained a continuous yarn of pure nanotubes when they were attempting to pull out a bundle of CNTs from a CNT array several hundred micrometres high and grown on a silicon substrate.

Jiang likened the process to "drawing a thread from a silk cocoon."

"(The discovery) was really a bit surprising for us," Jiang told China Daily, saying they nevertheless immediately became aware of its scientific implications.

The team's further research found that continuous yarns can only be drawn out from what they described as superaligned arrays in which CNTs are aligned parallel one to another.

Another interesting finding is the conductivity and strength of the yarns can be enhanced by heating them at high temperatures.

Jiang envisaged the yarns, after appropriate heat treatment, should be woven into a variety of macroscopic objects that can be used to create high-quality bullet-proof vests or materials that can block electromagnetic waves.

 

(China Daily Hong Kong Edition HE SHENG 10/26/2002)