Posted on 08/18/2005 9:53:53 PM PDT by Nachum
They're soft, strong, and very, very long.
Large, transparent sheets of carbon nanotubes can now be produced at lightning speed. The new technique should allow the nanotubes to be used in commercial devices from heated car windows to flexible television screens.
"Rarely is a processing advance so elegantly simple that rapid commercialization seems possible," says Ray Baughman, a chemist from the University of Texas at Dallas, whose team unveils the ribbon in this week's Science1.
Nanotubes are tiny cylinders of carbon atoms measuring just billionths of a metre across. They are light, strong, and conductive. But for years their promise has outweighed their utility, because the complicated processes involved in making devices from nanotubes were too slow and expensive to be used in large-scale manufacturing.
But now, nanotubes have gone into warp drive. Baughman's team can churn out up to ten metres of nanoribbon every minute, as easily as pulling a strip of sticky tape from a reel (see video ). This ribbon can be up to five centimetres wide, and after a simple wash in ethanol compacts to just 50 nanometres thick, making it 2,000 times thinner than a piece of paper.
The ribbons are transparent, flexible, and conduct electricity. Weight for weight, they are stronger than steel sheets, yet a square kilometre of the material would weigh only 30 kilograms. "This is basically a new material," says Baughman.
Nanoforest
Scientists have been weaving carbon nanotubes into fibres and sheets for several years (see 'Yarn spun from nanotubes' ). But until now, the most common way of making large sheets of nanotubes relied on a labour-intensive technique much the same as that used by the ancient Egyptians to make papyrus. Nanotubes suspended in a solvent were slowly filtered to create a mat, which was then dried and peeled off the filter.
A high voltage heats a nanotube sheet until it glows like a light bulb filament.
© Science
Baughman's team instead start with a 'forest' of half-millimetre-long nanotubes sticking upright on an iron-based platform. Pulling gently from the edge of the forest with an adhesive strip, such as a Post-It note, uproots a row containing millions of nanotubes. As these nanotubes pull out, they tangle with the next row, and so on.
The nanotubes tangle together just enough to keep a ribbon growing, without jumbling up into a huge ball. "They've found the magic spot," says Ian Kinloch, a materials scientist at the University of Cambridge. "A lot of people will now try this out with a Post-It in their own labs." The team says a one-centimetre-long forest of nanotubes can produce three metres of nanoribbon.
The researchers had previously used a similar method to draw strings of nanotubes from a forest2. Getting them to knit into a wider fabric is a bit trickier, but Baughman says that scaling the work up to produce large sheets will now be "easily do-able".
Patent bonanza
Nanotubes are already replacing graphite in certain commercial devices such as batteries. But this technique could now propel many more nanotube products into the marketplace, agrees Kinloch.
The team has already proved the sheets' usefulness in several applications, filing patents as they go. They have sandwiched a nanoribbon between two Plexiglass plates, for example, using the heat of a domestic microwave oven to weld the layers. This forms a transparent, conductive sheet ideal for a heated car window, they say.
And since bending does not change the electrical properties of the nanotubes they could be used to carry current in a 'rollable TV screen', something that has long been promised by nanotechnologists.
"Things move quickly if you can prove that the supply of the material is good," says Baughman.
NANO HATS
I think he was still making babies at age eighty. Gave geeks like me hope, LOL.
(ever notice his missing finger, lost in WWII?)
Nano Nano Hats? :-)
If it can heat a car window, I don't see why not.
DAMN, long johns for year round use.
Anybody remember the "UNION SUIT" with the drop bottom?
This material is so thin and light weight it inspires ideas. If it could be made opaque to infrared light, we could launch it into space and then open up a huge sheet of it between the earth and the sun. Then we could regulate the temperature of the earth. End of global warming.
Can the process generate a ribbon that is wide enough, fast enough to put up the space elevator?
If so, they should think about scrapping the next shuttle, and just put the heavy lift technology in place instead.
Thanks for posting it.
The Future is Now BUMP!
Yes, this stuff could make the space elevator/ladder practical.
We need a power source for that. aka Power Armor.
You put a large weight in roughly geosync orbit and run a very strong and lightweight cable back to earth. You hoist stuff up the cable like an elevator. If the cable is not strong, it breaks. If the cable is too heavy, it drags the geosync weight down.
space elevator article
http://www.space.com/businesstechnology/technology/space_elevator_020327-1.html
I have to think more on that, for my other questions, but, wouldn't that heavy weight out in space be, well ? weightless ?
This is INCREDIBLY exciting news!
MM
I should have said "large Mass" instead of large weight.
you're confusing weight with mass.
as much as i love the idea of the space elevator, i wouldn't expect anyone to build one for another hundred years, even if the nanotube technology is available now. It's rather expensive, sort of dangerous (imagine a long rope falling from the sky encircling the globe and leaving a wake of destruction around it's circumference. i read too much sci-fi i guess), and also complicated. On the plus side it would make getting into and out of orbit easy as pie.
If you put the mass at the orbital end beyond geosynchronus distance, but orbit it at geosynchronus speed, i.e., one orbit per day, it would want to pull away from the earth, keeping tension on the cable. The "elevator" would have to be directly over the equator, so as to avoid any north-south movement as seen from earth.
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