Please create an account to participate in the Slashdot moderation system


Forgot your password?

The World's Longest Carbon Nanotube 142

Roland Piquepaille writes "As you probably know, carbon nanotubes have very interesting mechanical, electrical and optical properties. The problem, currently, is that they're too small (relatively speaking) to be of much use. Now, researchers at the University of Cincinnati (UC) have developed a process to build extremely long aligned carbon nanotube arrays. They've been able to produce 18-mm-long carbon nanotubes which might be spun into nanofibers. Such electrically conductive fibers could one day replace copper wires. The researchers say their nanofibers could be used for applications such as nanomedicine, aerospace and electronics."
This discussion has been archived. No new comments can be posted.

The World's Longest Carbon Nanotube

Comments Filter:
  • Wow (Score:5, Funny)

    by jswigart ( 1004637 ) on Saturday April 28, 2007 @09:30PM (#18915257)
    So perhaps the internet will indeed become a series of tubes?
    • Re:Wow (Score:5, Funny)

      by Jeff DeMaagd ( 2015 ) on Saturday April 28, 2007 @09:37PM (#18915289) Homepage Journal
      Maybe. Maybe in an odd twist, the Internet might actually become a large fleet of nano-trucks.
    • Re:Wow (Score:5, Funny)

      by ScrewMaster ( 602015 ) on Saturday April 28, 2007 @09:39PM (#18915295)
      That's a scary thought ... Ted Stevens actually being prophetic, rather than just wrong.
      • Re:Wow (Score:5, Interesting)

        by Reality Master 101 ( 179095 ) <RealityMaster101 AT gmail DOT com> on Saturday April 28, 2007 @11:44PM (#18915795) Homepage Journal

        Ted Stevens actually being prophetic, rather than just wrong.

        You know, Stevens gets a totally bad rap on that whole thing. Exactly what is wrong with that analogy? Even UNIX uses the analogy with pipes; Ritchie* could have just easily called them tubes rather than pipes. And yes, the "tubes" of the Internet CAN get clogged up if there's too much flowing through them.

        I've never understood why he took such a beating about it. I guess some people are just determined to believe the worst about people, as though the guy though the Internet was literally air-filled tubes.

        • Re:Wow (Score:5, Informative)

          by espressojim ( 224775 ) <> on Sunday April 29, 2007 @12:28AM (#18915963)
          Maybe this is why? Even if the metaphor isn't horrible, the delivery was:

          Ten movies streaming across that, that Internet, and what happens to your own personal Internet? I just the other day got... an Internet was sent by my staff at 10 o'clock in the morning on Friday, I got it yesterday. Why? Because it got tangled up with all these things going on the Internet commercially.

          [...] They want to deliver vast amounts of information over the Internet. And again, the Internet is not something you just dump something on. It's not a big truck. It's a series of tubes. And if you don't understand those tubes can be filled and if they are filled, when you put your message in, it gets in line and it's going to be delayed by anyone that puts into that tube enormous amounts of material, enormous amounts of material.

          From wikipedia.
        • Re: (Score:3, Insightful)

          by Anonymous Coward

          Exactly what is wrong with that analogy?

          The context it was said in, he did not say "The Internet is a worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP) [Wikipedia]... You can think of it as a series of tubes...".

          Here's a clip [] with interesting parts from his speech.

          I'm also sure you can find the whole thing in the related clips pane. Listen to it (again?) and judge for yourself if he knows what he's

        • Re: (Score:3, Interesting)

          by ResidntGeek ( 772730 )
          When the tubes of the internet get clogged, it's not because of the tubes, it's because of the machines at the end. When tubes are clogged due to too much toilet paper passing through, you have to dig up the tubes and replace them. When a fiber-optic cable is clogged due to too many movies, you put faster routers at the ends - not at all like digging up a cable network all over the world. That's the problem with the analogy, it broke down *exactly* at the place he invented it for.
        • Ritchie* could have just easily called them tubes rather than pipes.

          Whatever happened to just calling them wires? I mean, like, DUUUH!
        • Re: (Score:3, Interesting)

          by Burpmaster ( 598437 )

          The analogy isn't too terrible. It conveys the notion that Internet bandwidth is a shared resource. However, Ted Stevens demonstrated very clearly that he has no idea what he's talking about. He seems to think that when somebody downloads a movie, the entire movie gets put into the 'tube' and all other data gets in line behind it. He thinks an e-mail he got several days after it was sent arrived late because too many movies were coming through the tubes. Not only that, but he referred to the e-mail as "an i

          • Re: (Score:3, Interesting)

            by 7Prime ( 871679 )
            I'm from Alaska. I fucking hate Ted Stevens, I think he's a jerk, and I disagree with about 95% of his politics. But an idiot he is most definitely not. He knew exactly what he was talking about... which actually worries me a lot more than if he didn't. He was attempting to explain it in layman's terms to a bunch of people, who, honestly, were a lot stupider than him. He has a tendancy to over-dumb-down statements like this.

            I think its kinda dangerous to assume that he's stupid, because you fail to realize
        • Re: (Score:3, Insightful)

          by hey! ( 33014 )
          The proof of the pudding is in the eating.

          The proof of the analogy is in the reasoning. Senator Stevens, if you recall, was blaming net neutrality for the fact that his email sent by one of his staff on Friday morning didn't arrive in his inbox until the following Sunday morning.

          So, yes, I think Senator Stevens deserves a round of jeers on this one. He's obviously bought a load of tosh about how net neutrality hurts users.

          In any case, the correct analogy would be: "The Internet is a NETWORK of tubes."
        • I guess some people are just determined to believe the worst about people

          ``Think the worst about people, and you'll usually be right.'' --Catbert.
    • by mrbluze ( 1034940 ) on Saturday April 28, 2007 @10:42PM (#18915591) Journal
      ... do you think they could be compensating for something?
  • by ian_mackereth ( 889101 ) * on Saturday April 28, 2007 @09:40PM (#18915301) Journal
    So, not only will we get light, cheap, immensely strong conductors, we'll also have a good market-driven reason to get all that valuable carbon out of the atmosphere!

    Voila! No more global warming!


  • Come again (Score:3, Funny)

    by Anonymous Coward on Saturday April 28, 2007 @09:44PM (#18915319)
    "Extremely long"?

    Perhaps 18 mm stands for... 18 million miles?
    • Re: (Score:3, Funny)

      by Anonymous Coward

      Perhaps 18 mm stands for... 18 million miles?
      18mm is extremely long for most nerds
    • Re:Come again (Score:5, Informative)

      by ian_mackereth ( 889101 ) * on Saturday April 28, 2007 @10:29PM (#18915545) Journal
      Just to get some perspective on this, 18mm is about a third of the length of good quality wool fibres.

      That puts it in the area of useable length for macro-sized application.

      • Re:Come again (Score:4, Informative)

        by evanbd ( 210358 ) on Saturday April 28, 2007 @11:04PM (#18915671)
        Well, they're still more slippery than wool, so that problem has to be solved too. But this is one piece of the puzzle, and it's very cool to see it coming along.
        • Point is, if they can go from the old-fashioned mess of nanometer-length tube fragments up to 18mm, that's 6 orders of magnitude longer. I know that blithely scaling up science is a major flaw of reporters, but I think there'll come a day when you can just grow a single tube a mile long, and weave them together like the core of a modern climbing rope (but obviously less stretchy).
          • by Eivind ( 15695 )
            Doesn't matter much. Once the tubes are long enough that they can be weaved or epoxied and they'll break before they slip, there's little added advantage from having the things be even longer.

            If a weave of 10cm long fibres of some material is already failing by fibres breaking rather than fibres slipping, there's not much to be had from the fibres being instead 1 meter or 10 meter long individually.

            I'm certain that 18mm long nanotubes are already long enough that a rope made of such would have 90%+ of t

            • You sound like you know your rope, and I don't, so by no means do I think this is right, but ...

              When a traditional fiber breaks, it's slipping on a molecular level. With macroscale nanotubes, the breakage would be right down at the covalent bond level, theoretically giving it a tensile strength on the same order as a perfect diamond. Admittedly, I don't know if that's any good or not.
              • by Eivind ( 15695 )
                True, a carbon nanotube only breaks when the actual molecule breaks. True, this give humongous tensile strength.

                Strengths in the 60 - 100 GPa-range have been measured, which is fairly impressive when you consider that high-tensile steel tops out around 1.2 so basically, a carbon nanotube-rope of a given thickness should be able to hold 50-90 times the load that a similarily thick steel-cable can hold.

                But it gets better; carbon nanotubes are (unlike steel) ligthweigth. Often, strength in relation to thic

              • by Eivind ( 15695 )
                Oh, and incase you still don't get what all the "fuzz" is about, here's one more property to make you drool over nanotubes;

                They conduct heat along their length *insanely* well.

                If you take a square-meter of meter-thick copper and heat one side of the block so that it is 1 degree C (or K, same thing in this case) warmer than the other side, then 385W of power leaks through. A lot. Copper is a good thermal conductor. (as any overclocker would know.)

                The same number for a block of tigthly compressed, perfe

                • Mr. McGuire: I just want to say one word to you - just one word.
                  Ben: Yes sir.
                  Mr. McGuire: Are you listening?
                  Ben: Yes I am.
                  Mr. McGuire: 'Nanotubes.'
      • by miro f ( 944325 )
        wait, so you're saying, the ultimate goal is to be making jumpers and socks out of carbon nanotubes?
        • by 7Prime ( 871679 )
          Let me just put on this nice comfy pair of carbon-nano-tube boxers, before you shoot me in the crotch.

          See... the bullet just bounced off... "balls of steel," I tell ya!
      • Re: (Score:3, Interesting)

        Just to get some perspective on this, 18mm is about a third of the length of good quality wool fibres.

        That puts it in the area of useable length for macro-sized application.

        IIRC when Popular Mechanics discussed these nanotubes for building our space elevator, one of the technical hurdles they mentioned was needing nanotubes ~18" in length for the structure to be sound.

        Obviously we've got a long ways to go then.

        The other thing they mentioned was that given a mathematically perfect carbon nanotube structure, the highest building we could build before it would collapse on itself is something like 90 miles; and we need

        Of course both of these are hearsay so take them with a grain

        • Re: (Score:3, Informative)

          by dcmeserve ( 615081 )

          given a mathematically perfect carbon nanotube structure, the highest building we could build before it would collapse on itself is something like 90 miles... ..the height required for a space elevator/cable is several orders of magnitude greater

          Carbon nanotubes have their strength in tension, not compression.

          A self-supporting building based on nanotubes would have to be a tensegrity structure of some kind, where you'd have nanotubes pulling against something else that's relatively incompressible; mayb

    • you know that nanotubes are usually on the order of 10-100 nanometers wide, which is 10-100*10^-9 meters, so 18mm would be 18*10^-3 - 6 orders of magnitude difference
    • Its about 10000 times longer than what you get when you buy single walled carbon nanotubes at a chemical supplier, like alfa aesar.

      Thats hardly something to sneeze about.

      They are long enough to, for example, actually connect two macroscopic devices, for example two dies on a MCM.
    • It's a relative term - extremely long compared to their diameter. These are about a million times longer than they are wide.
  • by sycodon ( 149926 ) on Saturday April 28, 2007 @09:48PM (#18915337)
    Nano nano nano.
    • Re: (Score:2, Informative)

      by mark-t ( 151149 )

      That's na-NU, my man....

      My understanding is that writers originally wrote the it as nano, and so in particular first season merchanise often used that spelling, but Robin Williams pronounced it as nanu.

  • by pestie ( 141370 ) on Saturday April 28, 2007 @09:55PM (#18915381) Homepage
    Did I get it right in the subject line? Apparently all Slashdotters are supposed to hate this Roland guy, right? God, I just want so desperately to be loved...
    • by sohare ( 1032056 )
      You have done your duty well, comrade.
    • Re: (Score:3, Informative)

      by ColaMan ( 37550 )
      While I don't condone his actions in the past (that is, using /. to push more views to his site for personal gain), he doesn't link-through his site anymore. So now, he's just another submitter of crappy stories that generally give off wildly over-optimistic expectations of future possibilities.

  • Yay for buckyballs!
  • by SeaDour ( 704727 ) on Saturday April 28, 2007 @10:19PM (#18915509) Homepage
    Can these "nanofibers" be used to make a space elevator ribbon? Or does that system require a different method of employing carbon nanotubes?
    • Re: (Score:3, Insightful)

      by QuantumG ( 50515 )
      Two points I like to make about the space elevator:

      This isn't tomorrow's technology, it is something the human race might do a hundred years from now.

      If we have the super strong, super light materials needed to make the space elevator, what else might we do with them? Might we not make better rockets? Or better planes? Might we not make single-stage-to-orbit vehicles which so drastically reduce the price of launch costs that building a space elevator is not only possible, but unnecessary?
      • Those would have to be some *drastically* reduced prices to compete with a space elevator. Accelerating to escape velocity is always going to take a lot of fuel, where with the space elevator it's not even an issue.
      • by camperdave ( 969942 ) on Saturday April 28, 2007 @11:47PM (#18915815) Journal
        Might we not make single-stage-to-orbit vehicles which so drastically reduce the price of launch costs that building a space elevator is not only possible, but unnecessary?

        The problem with rockets has never been the mass of the rocket, but the mass of the fuel. There's only so much oomph you can get out of a million litres of hydrogen and oxygen chemically, and it's only marginally more than the power it takes to lift a million litres off the surface and into space. Sure, a lighter fuel tank, and lighter payload will help, but not significantly.

        No, if we want cheap access to space, we either go nuclear [], or build some sort of space elevator. While we may just be at the threshold of being able to make materials with the tensile strength needed for a beanstalk, we have the tech to make gas core nuclear rockets right now.
        • by evanbd ( 210358 ) on Sunday April 29, 2007 @12:23AM (#18915943)

          It's not about the fuel prices. Never has been, and won't be for the foreseeable future. Propellant is cheap, it's the vehicle that's expensive. Elon Musk of SpaceX was recently quoted as saying propellant costs are comparable to the accounting errors.

          Remember that the space elevator has to supply all the energy to the payload too, but it has to get it in a much more expensive form -- like electricity beamed from the ground by lasers or some such. Rockets aren't actually all that energy inefficient in comparison.

          I used to be a huge fan of the space elevator idea, but then I started looking what those same materials do to rockets. SSTO is just the start. And remember, those materials will change rockets long before they make a space elevator.

          Of course, I am a rocket engineer, so I might be a little biased, but I've also examined the problem in some detail :)

          • If you are really a "rocket engineer" (what kind, 4th of july ones?), then you have a really narrow horizon.
            Try to imagine how many launches you would need to, for example, build a mining and refining base on an asteroid. 25 million tons, in an escape orbit, anybody?
            Thats a 1000 times of all launches in human history, for something that might be just a little thing if we ever go interplanetary.
            Try a quick calculation of how it would cost...

            You might be thinking in current terms "All we send up is highly tec
          • by dbIII ( 701233 )

            Remember that the space elevator has to supply all the energy to the payload too, but it has to get it in a much more expensive form -- like electricity beamed from the ground by lasers or some such.

            I never really understood this bit. There you are with a highly conductive material that will conduct that same as graphite sheets in the high strength direction (which is straight up the wire) and people are talking about broadcast power? Even if it is well columnated not a lot of power is going to hit your

            • by evanbd ( 210358 )
              The problem is that the wires have resistance. And they're thin -- the elevator is thin. So the resistance is non-trivial. It might be tiny, but it's not zero, and over thousands of kilometers it adds up. It's not impossible, and whether it's better or worse than beamed power depends on who you ask and what assumptions you make -- ie if you can get ballistic conduction [] working for that length of nanotube. Also, it needs to be at very high voltage (to keep the current and I^2*R losses low), which makes
        • by Hatta ( 162192 )
          While we may just be at the threshold of being able to make materials with the tensile strength needed for a beanstalk, we have the tech to make gas core nuclear rockets right now.

          Do we have the tech to deal with the fallout of the inevitable accidents?
        • by TEMMiNK ( 699173 )
          The problem being that you put the words Nuclear and Rocket together and the Russians get really nervous, and nobody likes a nervous nuclear power.
        • by init100 ( 915886 )

          we have the tech to make gas core nuclear rockets right now.

          With nuclear rockets, you would have to solve vast PR problems though. Just consider the demands by the greens to close nuclear power stations, which are firmly on the ground. A nuclear-powered rocket, with the significant risk of an accident and its fuel being released into the environment, could face much more severe problems than nuclear power stations.

          Even to me, who is usually pro-nuclear, it isn't clear that nuclear rockets launching from the surface of the earth is a good idea. Considering the hi

      • This isn't tomorrow's technology, it is something the human race might do a hundred years from now.

        I think you're wrong about that, as do the people doing most of the research on the subject.

        In this article [] covering Brad Edwards' NASA-sponsored research into Space Elevator technology, his completed work under a $500,000 NASA research grant reveals the technological and economic feasibility of space elevators.
      • by tsa ( 15680 )
        A space elevator contains so much carben we should build it just to get rid of our pesky global warming problem. Grow plants to take the CO2 out of the air, turn them into space elevator, and Bob's your uncle!
  • Carbon fibre (Score:4, Interesting)

    by TapeCutter ( 624760 ) on Saturday April 28, 2007 @10:23PM (#18915519) Journal
    Apart from more tubes for the interwebs, I would imagine that 18mm is also long enough to make carbon fibre products that are lighter and stronger than what is currently available. I wonder if an America's Cup or F1 winner will one day be built from nanotubes?
    • Re: (Score:3, Interesting)

      by evanbd ( 210358 )

      Note that nanotubes != CF.

      That said, people are already starting to incorporate nanotubes in composite materials. The two hard parts are that they're really slippery and it's hard to get the matrix to stick to them, and that they tend to clump up a lot. The increased length helps with the first problem -- slippery is less of a problem if there's more surface to stick to. I don't know about the dispersion.

      Nanotube composites are already impressive. You can get things with 30-50% more stiffness, 50-20

    • by samkass ( 174571 )
      Isn't carbon fiber that's microscopic in one dimension but macroscopic in the other the whole reason asbestos and other mesothelioma-causing "breathable" carbon structures banned? Is this just a way to manufacture lung cancer, or is there something about nanotubes that makes it not do the same thing asbestos does to the lungs?
  • by camperdave ( 969942 ) on Saturday April 28, 2007 @10:35PM (#18915563) Journal
    18 millimetres? Great, only 99,999.999982 km to go!
    • Perhaps it'll be like Moore's law. If the length doubles every 18 months, it'll less than half a century.
  • In other news, Bjorn Stevens, world's tallest midget, and jumbo shrimp decry military intelligence in Iraq peace action.

  • Great... (Score:4, Funny)

    by DoofusOfDeath ( 636671 ) on Saturday April 28, 2007 @11:15PM (#18915707)
    Now we're going to get spam advertising ways to lengthen our nanotubes...
  • will be when someone figures out how to either join these fibres together, or grow a continuous nano-scale monofilament.
    Then we will really see what Arthur C was talking about.
    The applications for "diamond" fibre are enormous.
  • some perspective (Score:5, Informative)

    by Goldsmith ( 561202 ) on Sunday April 29, 2007 @12:06AM (#18915881)
    Although the PR person who wrote this obviously thinks this is a major breakthrough, these guys are using a method which was originally invented by Japanese researchers three years ago (google for "CNT super growth"). The Japanese guys have since focused on getting the fastest growth rate possible (I think it's about 0.2mm/min... if you want to figure out how many, many years it would take to grow a space elevator). There are lots of people working on improving this growth method, 18mm arrays may be the longest, but it seems to be in the same range as other people working on the "super growth" method. That doesn't diminish this research, rather it means that this method is very likely to work in the long run for industrial scale growth of nanotubes for materials (more simply, it's easily reproducible, and people want "nano-enhanced" golf clubs).

    Isolated nanotubes have been grown longer than this (I've grown isolated nanotubes longer than this, and I'm not a growth specialist), as have bundles of nanotubes. This is the longest array of pure, aligned, continuous nanotubes.
    • by khallow ( 566160 )
      What makes it not a major breakthrough? One of the problems with carbon nanotubes is that they don't adhere well to a resin matrix. A propose solution was to make really long nanotubes. 18 mm is really long. If they can make it in bulk, then they can make, for example, the space elevator tether. Even 0.2 mm/min is a sufficient growth rate if you're making enough (in orders of magnitude) carbon nanotubes at a time.
      • If no one could make really long nanotubes, yeah it would be amazing, but arrays like this are routinely made several millimeters in length, and some people make single nanotubes ~150 mm long.

        The technology does not yet exist to piece together nanotubes strongly enough to make a space elevator... which is why I was careful to use the word "grow." If one could piece nanotubes together well enough, then everything does get much easier.
        • by khallow ( 566160 )
          I guess I don't see the problem. Are there quality control problems with these lengths (eg, many flaws for the length)? They seem sufficiently long even with a weakly bonding resin. I don't see the reason one couldn't make an adequate space tether from Earth to past geostationary with these lengths. For example, in the paper, "Direct Spinning of Carbon Nanotube Fibers from Chemical Vapor Deposition Synthesis" [] by Ya-Li Li, Ian A. Kinloch, Alan H. Windle, they claim to (among other things) spin a thread with
          • I see where you're going with that, but the intertube tensile strength doesn't scale with length. Binding energy is different from tensile strength. The work which you're doing in pulling apart nanotubes depends on how the binding energy changes with time, not so much on the total energy. If you pull a 100nm section of a nanotube out of a bundle, you could think of it costing the entire binding energy, but then you get back 100nm less than the starting binding energy when you stop So the end cost of tha
            • by khallow ( 566160 )
              Drat, I see your point. You might be able to get top performance if the structure isn't loaded normally, but doesn't seem viable for cables under heavy loads for years at a time.
  • a clarification (Score:1, Informative)

    by Anonymous Coward
    This is not the record for longest tube ever grown. Groups have grown single tubes the size of their substrate wafers (4 inches usually). This group grew a long bundle of CNTs. In the field we call these 'forests'--imagine a lawn, but at the nanoscale. The blades of grass are the CNTs poking up off the surface.

    Remember also that the figure of merit of a CNT when used for its mechanical properties is the growth defect density per meter, and even for the best growth techniques so far this ends up being
  • I don't normally complain about mods/tags etc (seems a bit pedantic), but how did this get tagged as 'biotech'?

    Is the word 'carbon' enough to be classified as 'biotech'? Is a pencil 'biotech' now?

  • RTFA (Score:2, Informative)

    by Raynor ( 925006 )
    It would be nice if people actually read up the subject before posting this garbage...

    This is not "The World's Longest Carbon Nanotubes." It's the longest mass-producable parallel carbon nanotubes.
  • Here's what I remember from last time...

    To be held up, a space elevator needs a FABRIC with a tensile strength of about 65GPa.
    To build it, you'd want a safety factor of about two, thereby a tensile strength of about 120-130GPa.

    I do not know the specs of the tubes from TFA, however

    Very short INDIVIDUAL single-walled carbon nanotubes have been created (in a lab, in small quantities, using processes that may be prohibitively expensive) with measured individual fiber strength of about 60GPA.
    "Very long" ones wer
  • Nanometers wide, millimeters long. Isnt that an aspect ratio approaching a million?

I have ways of making money that you know nothing of. -- John D. Rockefeller