Carbon Nanotubes 1 KM Long

Posted on Sep 19, 2009 in Geek News, Random

http://www.hightech-edge.com/carbon-nanotubes-1km-long-sheets-nanocomp-technologies/5068/

New manufacturing process produces yarns and sheets of carbon nanotubes millions of times the size of previous nanotubes.

The thought of being able to use carbon nanotubes in future projects excites most engineers, but the current size at which they can be produced, renders them pretty much useless. That is until now.
Thanks to Nanocomp Technologies of Concord, New Hampshire, researchers and engineers can now utilize ‘yarns’ and ‘sheets’ of the material.
When carbon nanotubes first entered the spotlight back in 1991, the technology world began brainstorming endless ways the material could be used. The structural, thermal, and electrical properties of these cylindrical-shaped carbon molecules meant that, in theory, they could be used for extremely compact and fast digital computers, rugged electronics, and super strong structures such as a space elevator – a 62,000 mile elevator stretching into space.

However, researchers have found it difficult to mass produce nanotubes long enough to accomplish any break-through technologies.
Now Nanocomp Technologies, based in Concord, New Hampshire, is bringing the future closer by producing yarns and sheets of nanotubes, in bulk.
On an atomic level, carbon nanotubes look like rolled-up tubes of chicken wire. The tubing is made from a hexagonal lattice of carbon atoms and measures approx one nanometer (one billionth of a meter) in diameter.
Currently, nanotubes are commonly produced in segments about 10,000 nanometers long, to the eye, this looks like a black powder. At this size, the carbon nanotubes full potential is far from utilized, but Nanocomp says it can now produce 18-square-foot sheets and 1 km long yarns of nanotubing.
Nanocomp is using its nanotubing to make lightweight antennas, cables, and electromagnetic interference shields for the military and aerospace markets. Nanocomp is also working with the Office of Naval Research and the U.S. Army’s Natick Soldier Center to develop better body armor.

How It Works

Nanotubes are made by feeding a gas containing a carbon-based feedstock – the raw material – into a long cylindrical furnace. The gas is swept along the furnace until it meets a heated, porous block that is coated with a catalyst.

As it squeezes through the pores, the gas is forced into contact with the catalyst, and carbon nanotubes begin to form. A temperature gradient between the porous block and the open end of the furnace supports the tubes as they grow, absorbing material from the reaction gas.
Eventually the nanotubes leave the cylindrical furnace, looking like a wispy, black mass of tube-shaped cotton candy. A rotating anchor or conveyor belt captures the nanotubes as they emerge, turning them into yarns and sheets.