David Kirkpatrick

November 10, 2009

Carbon nanotubes are the wiring of the future

Filed under: et.al. — Tags: , , , , — David Kirkpatrick @ 3:16 pm

Previously I’ve blogged about carbon nanotubes replacing copper wiring, and here’s news of a new manufacturing technique that gets that idea closer to the mainstream. This shift in wiring is most likely a “when” instead of an “if.”

From the second link:

A new method for assembling carbon nanotubes has been used to create fibers hundreds of meters long. Individual carbon nanotubes are strong, lightweight, and electrically conductive, and could be valuable as, among other things, electrical transmission wires. But aligning masses of the nanotubes into well-ordered materials such as fibers has proven challenging at a scale suitable for manufacturing. By processing carbon nanotubes in a solution called a superacid, researchers at Rice University have made long fibers that might be used as lightweight, efficient wires for the electrical grid or as the basis of structural materials and conductive textiles.

Others have made carbon-nanotube fibers by pulling the tubes from solid hair-like arrays or by spinning them like wool as they emerge from a chemical reactor. The problem with starting from a solid, says Rice chemical engineering professor Matteo Pasquali, is that “the alignment is not spectacular, and these methods are difficult to scale up.” The better aligned and ordered the individual nanotubes in a larger structure, the better the collective structure’s electrical and mechanical properties. Using the Rice methods, well-aligned nanotube fibers can be made on a large scale, shot out from a nozzle similar to a showerhead.

The late Nobel laureate Richard Smalley started the Rice project in 2001. Smalley knew solution-processing would be a good way to assemble nanotube fibers and films because of nanotubes’ shape. Carbon nanotubes are much longer than they are wide, so when they’re in a flowing solution, they line up like logs floating down a river. But carbon nanotubes aren’t soluble in conventional solvents. The Rice group laid the foundations for liquid processing of the nanotubes five years ago, when they discovered that sulfuric acid brings the nanotubes into solution by coating their surfaces with positively charged ions.

Nanotube fiber: This fiber, which is about 40 micrometers in diameter, is made up of carbon nanotubes.
Credit: Rice University