Researchers Uncover Secrets Behind Nanotube Formation

[phantom power]

A multinational team of scientists has discovered that multi-walled carbon nanotubes made by the pure carbon arc method are, in fact, carbon crystals that form inside drops of glass-coated liquid carbon. The research appears in the 11 February 2005, issue of the journal Science.

One way to make nanotubes involves using a carbon arc to heat graphite to about 5,000 C. An electrical current is passed through the graphite in a chamber filled with helium gas. The result is a sooty deposit on one of the electrodes that contains columns filled with nanotubes.

"We were doing research on the electrical transport properties of carbon nanotubes when we noticed that the nanotubes had these little beads that looked like liquid drops on them, said lead author Walt A. de Heer, physics professor at the Georgia Institute of Technology.

Since the nanotubes in the interior had a crystalline structure, the team reasoned that the liquid carbon on the inside of the drops had cooled so slowly it became a supercooled liquid, which is a liquid below the temperature which normally turns it into a solid. As the temperature of any supercooled liquid drops to a certain critical temperature, it begins to crystallize. Which in this case, researchers reasoned, resulted in the orderly molecular structure of the nanotubes.

http://www.sciencedaily.com/releases/2005/02/050213121231.htm

[On the Road]

1. Does This Mean They're Easier to Manufacture?

That would be good news for the space elevator people.

[phantom power]

3. I predict it will eventually lead to improvements.

Understanding the details of how a process occurs usually allows for better optimization of that process.

I'm not sure if the LiftPort Carbon guys are planning to use this process for generating their composites, or not. There are other ways to grow nanotubes, which might lend themselves better to manufacturing macroscopic composite fabrics.

[whistle]

2. And the possible applications of this new research are.....

...somewhat dangerous, environmentally dangerous and perhaps even quite toxic???

<snip>

But carbon nanotubes are also inert and chemically stable, which has made it difficult for chemists to create nanotube derivatives -- tubes decorated with extra molecules that act as chemical "handles" for further manipulation. Most processes that laboratory researchers have used to create nanotube derivatives are impractical on a macro scale because they involve the use of extremely high temperatures, high pressures or other techniques that are difficult to reproduce in a production setting.

Fluorine, which is often shunned by chemists because of its highly reactive nature, has proven to be very useful as an alternative means of creating nanotube derivatives, precisely for that reason. The addition of fluorine opens the door to subsequent chemical reactions, giving chemists the ability to attach other types of molecules to nanotubes.

So far, Margrave and his colleagues have used this process to create dozens of "designer" nanotube derivatives. These include hydrotubes, which contain hydrogen in an activated form; hexyl nanotubes, methoxy nanotubes, amido nanotubes, and other varieties containing organic side chains; polymers similar to nylon; and hydrogen-bonded nylon analogs. Unlike pure carbon nanotubes, all these derivatives are soluble in traditional organic solvents.
<more>

<link> http://www.sciencedaily.com/releases/2002/04/020412081030.htm

[phantom power]

4. perhaps, but then perhaps this might eventually give us

the solar system. Or, at least it might give us new "super-composites".

Toxic by-products can be dealt with, if people are willing to regulate the manufacturing. (not that the current political climate is inspiring much regulation...)

[whistle]

5. no political climate ever imposes regulations which cut into...

...profits, which is what the game apparently is all about in this country. Nuclear imposes risks that are astronomical in their impact if allowed to get out of control The history of the profit motivated nuclear industry is to evade regulatory requirements until they are caught and then for thousands and potentially millions of innocent and unsuspecting people the results are disastrous. Even the risk of exposure is dealt with by the nuclear industry with cover-ups, intimidation and even elimination of the whistle blowers. That makes them 1,000 times perhaps even a million more dangerous then say the big tobacco or pharmaceutical industries.