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World Record: Four-Centimeter-Long Carbon Nanotube
colonist writes "University of California scientists at Los Alamos National Laboratory and chemists from Duke University have recently grown a four-centimeter-long, single-wall carbon nanotube (SWNT): a new world record. Previous SWNTs were a few millimeters long. Yuntian Zhu and his colleagues used a process called 'catalytic chemical vapor deposition' from ethanol (alcohol) vapor. From their abstract: 'Our results suggest the possibility of growing SWNTs continuously without any apparent length limitation.' Zhu: 'although this discovery is really only a beginning, the continued development of longer length carbon nanotubes could result in nearly endless applications. Actually, the potential uses for long carbon nanotubes are probably limited only by our imagination.'"
Space elevator, here we come!
I was going to post something about "could we spin these in space and spool them through the atmosphere for a space elevator, then I saw the growth rate:
11 micrometres a second!
Unless I've flubbed my math, that's over 4 days to grow the short length - not saying that's not a damned good thing, as we _need_ material if we're to get Out cheaply, but production speed is almost as important as strand length.
Negativity aside (sorry, it's my nature); good work guys, keep on growing/going.
" Actually, the potential uses for long carbon nanotubes are probably limited only by our imagination.'"
And so begins the hype machine to ramp up. Don't get me wrong nanotubes have some neat applications but there is quite a gap from that to uses "limited only by our imagination".
Remember only you can stop scientific hype.
Well.... since we're likely talking about a *woven* nanotube mesh, why would we only have one process for growing the thread? Paralell nanotube growth would cut the time required to build a ribbon to the sky quite a bit.
Of course, by your math, we'd need at least a dozen and a half processesseseseseses -- processi? Processions?
"Times have not become more violent. They have just become more televised."
-Marilyn Manson
Smoke is where the first place that buckyballs and nanotubes were discovered.
Yes, and chornic smoke inhalation leads to lung cancer. So I take it that you were agreeing with original poster.
.
-shpoffo
so what part of smoke is causing cancer again?
no not just cigarette smoke - any smoke
Following up to your own reply, a carbon nanotube has properties which are either metallic or semiconductive, depending on the chirality of the tube. Each tube is essentially a rolled-up piece of graphene (single layer of graphite), which has a hexagonal crystal lattice. If you imagine taking a sheet of that hexagonal structure and rolling it into a tube, there will clearly be a line along which the two opposite edges join, kinda like the line that runs up the back of the stocking.. :-) If you roll the sheet up perpendicularly to the axis of the nanotube, you get (basically) a bunch of rings of hexagons. If there's a bit of twist, you get spirals of hexagons. These two structures would have different chirality - the number of hexagons around the circumference of the tube matters, too.
To make a long story short (too late), by controlling the amount of twist in the nanotube you can determine whether that particular nanotube will be a metal or a semiconductor, and (I believe) can control the bandgap as well. Now, if we can just learn to control the chirality easily and cheaply...
Anyone with more experience in carbon nanotubes, please chime in. I'm only a few weeks into a graduate class in nanotubes, and may have missed a subtlety or two.
Ce n'est pas un vrai mouvement de robot!