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New Form of "Mobius" Carbon Predicted

Posted by kdawson on from the with-a-twist dept.

KentuckyFC writes "We've seen carbon nanotubes, buckyballs, and chickenwire. Now materials scientists have created a computer model of a Mobius strip fashioned from strips of graphene — a molecule that would have a single surface and only one edge. (Other groups have made Mobius-like organic molecules but never out of carbon sheets.) The model allows the researchers to determine the physical and chemical properties of the molecules and how these depend on the number of twists in the strip. The team says, for example, that 'Mobius carbon' should be stable to temperatures of at least 500 Kelvin (abstract). But the most exciting prediction is that strips with an odd number of half twists should have a dipole moment that would cause them to self-organize into a crystal. That implies that there's a new type of carbon made entirely of Mobius strips ready to be made by any chemists with a good supply of graphene (maybe these guys)."

33 of 115 comments (clear)

  1. 1st post by Anonymous Coward · · Score: 2, Funny

    I wrote the first post on the Moebius strip I wrote the first post on the Moebius strip

  2. Insight required by w0mprat · · Score: 4, Interesting

    Do these have useful properties at all? Where's the (wild and unfounded) speculation?

    paper: http://arxiv.org/abs/0903.2080

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    1. Re:Insight required by InsertWittyNameHere · · Score: 4, Funny

      Not as useful as inanimate carbon rods!

    2. Re:Insight required by Laser_iCE · · Score: 3, Funny

      All hail the INANIMATE CARBON ROD!

      In Rod We Trust.

    3. Re:Insight required by elashish14 · · Score: 5, Interesting

      Graphene has some pretty interesting electronic properties. Its bandgap (the essential component of all semiconductors) can be manipulated by changing the length of the sheet; as the sheet becomes infinitely long, the bandgap approaches zero. As a result, it could hold potential in photovoltaics for light capture or LEDs for light emission where capture/emission is tunable based on the size of the particle (which is pretty easy to manipulate).

      Another article popped up on Slashdot recently suggesting graphene could be used for super high-capacity memory storage: http://hardware.slashdot.org/article.pl?sid=08%2F12%2F18%2F2332251.

      From the paper they mention that active electrons have near-zero effective mass. Since electron mobility is inversely proportional to effective mass, resistivity approaches zero (in essence, we approach superconductivity). As far as twisted graphene ribbons go, the paper only mentions that there's some weird ground state orbital morphologies (triplet states and open singlet ground states) which I'm not familiar with but also have to do with interorbital transition which always has applications in light emission/absorption technologies. I believe that lasers heavily depend on triplet states to create inversion layers, but don't quote me on that.

      As far as it goes anyway, even if you don't know what the properties will be, you might as well study it - you never know what's going to come out.

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    4. Re:Insight required by TapeCutter · · Score: 4, Informative

      "[nanotubes]...currently impossible to make more than a trace amount of."

      Only for large values of "trace amounts" such as this proposed 400 ton/yr plant that when completed will compete with existing plants.

      Also it maybe obvious to some but I'm having difficulty is understanding how this discovery would help in production of said nanotubes?

      --
      And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
    5. Re:Insight required by InsertWittyNameHere · · Score: 2, Informative

      If I have to explain it it's not funny!

    6. Re:Insight required by BobisOnlyBob · · Score: 2, Funny

      Look between your legs.

  3. Man, I heard that by B1oodAnge1 · · Score: 3, Funny

    A Mobius strip is bad for your back.
    I think I'll just stick with the Pole strip for now thanks.

    --
    RUGBYRUGBYRUGBY
  4. Only one side... by LaminatorX · · Score: 4, Funny

    Can you imagine a Klien Bottle made of these?

    1. Re:Only one side... by AstrumPreliator · · Score: 3, Funny

      Yes I can, but can you imagine a Real Projective Plane made of these? Neither can I =(.

    2. Re:Only one side... by reverseengineer · · Score: 3, Insightful

      I think you could make a molecular Klein bottle, though of course you would have the same limitation as for any Klein bottle immersed in three dimensions- a self-intersection would be necessary. This would probably rule out a physically realizable Klein bottle made purely out of graphene, as a self-intersection would either involve carbon atoms bonding to 5 or 6 other carbon atoms (extraordinarily unlikely) or bonds with significant angle strain and steric hindrance if you tried to squeeze the self-intersecting tube through the lattice instead of bonding to it. If you didn't mind including some higher-valent atoms rather than just carbon, it could probably be constructed.

      --
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    3. Re:Only one side... by yo303 · · Score: 4, Funny

      A mathematician named Klein
      Thought the Mobius strip was divine.
      Said he, "If you glue
      The edges of two
      You'll get a weird bottle like mine."

  5. one side chemical reactions... interesting by StupidPeopleTrick · · Score: 3, Interesting

    I am wondering the chemistry applications of this. I bet you can make some very interesting compounds out of this material. A one sided molecule kind of redefines limiting agent would it not? - StupidPeopleTrick

    1. Re:one side chemical reactions... interesting by onepoint · · Score: 3, Interesting

      I am having a hard time picturing a 1 sided molecule. I would guess I can picture 2 sides ( top / bottom ) but 1 side? way more advanced than I can currently think, can someone offer an example.

      --
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    2. Re:one side chemical reactions... interesting by NemoinSpace · · Score: 3, Funny

      Start over again with Hydrogen, now take the BLUE pill.

    3. Re:one side chemical reactions... interesting by zygotic+mitosis · · Score: 3, Funny

      We are talking Mobius Carbon, not Morpheus Carbon

    4. Re:one side chemical reactions... interesting by MrNaz · · Score: 3, Interesting

      To be honest, calling a Mobius Strip "one sided" is not strictly correct. It's just a twist that causes one side to join with the other such that all points on both sides can be traced to each other without having to traverse an edge. Clever, yes. Truly one-sided in the dimension collapsing sense? No.

      Mobius Strips are great for befuddling stupid people though. If you tell the average person that you can show them a piece of paper with one side they laugh. Then you give them a Mobius Strip and a pencil, draw a dot on it and ask them to draw a line along the strip. When they meet up you can almost hear their brains grinding gears.

      Taking the piss out of idiots FTW!

      --
      I hate printers.
    5. Re:one side chemical reactions... interesting by Gibbs-Duhem · · Score: 2, Informative

      Graphene is a (basically) 2-D sheet that can be fairly large. Imagine the sheet the size of a blanket. Now make a mobius strip out of it.

      The fact that it's "one sided" should only really come into play in that long range hybridization of the pi orbitals will interfere with each other -- presumably causing the weird effects their model predicts.

    6. Re:one side chemical reactions... interesting by Gibbs-Duhem · · Score: 2, Informative

      Doubt it. Things can still react on both sides of the locally 2-sided graphene sheet.

    7. Re:one side chemical reactions... interesting by reverseengineer · · Score: 5, Informative

      Locally (to the individual atoms, for example) a Mobius molecule is double-sided. Each carbon atom is fixed in a plane in graphene, though the point here is that the plane is interestingly warped. A chlorine atom could attack a carbon atom from above the plane and a bromine atom could attack from below the plane, and that would be a physically meaningful description. "Above" and "below" are of course arbitrary distinctions; let's use "a" and "b" in this post. From the perspective of Carbon #1 of the 150 carbon atoms in this molecule, the situation is nothing special; there's a bit more bond strain from the way the lattice is twisted, but it still generally behaves like a carbon atom.

      What makes a Mobius molecule interesting is when you something else along its surface. For example, kinesin is a protein that works like a set of molecular legs. Picture a regular, non-Mobius single-walled carbon nanotube, a rolled-up sheet of graphene. This tube has an exterior surface (the "a" position)and an interior surface ("b")- it is two sided. To get a kinesin molecule from the exterior surface to the interior surface or vice versa, you must either cut through the graphene lattice or walk to an edge of the cylinder and flip around. There is not a smooth, continuous path from position Carbon #1-a to #1-b for a regular nanotube.

      However, for a Mobius nanostrip, that added half-twist makes the "exterior surface" continuous with the "interior surface," making a smooth path possible. If you place kinesin at Carbon #1-a and have it walk around the strip, halfway through the course (for a strip with one half-twist), the kinesin will be at Carbon #1-b (in other words, back at Carbon #1, but in a local sense, on the other side of the sheet), and its orientation will be flipped 180 degrees from the original. If the kinesin keeps going, eventually it returns to its original orientation at Carbon #1-a. If you put a kinesin molecule at both 1-a and 1-b and sent them off walking in opposite directions, they would eventually collide.

      Locally, 1-a is on the opposite side of 1-b, but a kinesin molecule can smoothly and continuously walk from 1-a to 1-b (or any other point) without breaking bonds in the graphene lattice or flipping around an edge to another side. Therefore, in terms of its entire shape, a Mobius molecule is one-sided.

      --
      "FDA staff reviewers expressed concern about the number of patients who were left out of the study because they died."
  6. Bike Frames? by MarkvW · · Score: 2, Interesting

    Will this do anything for bicycle frames?

    1. Re:Bike Frames? by syousef · · Score: 5, Funny

      Will this do anything for bicycle frames?

      Yes. Now you'll be able to rid a bike on Venus. You'll disintegrate in 30 seconds but the bike frame won't. Have a nice ride.

      --
      These posts express my own personal views, not those of my employer
    2. Re:Bike Frames? by rubycodez · · Score: 2, Funny

      no, but if you put a sheet of them in a clothespin with the end in the spokes, they make a neat engine sound

    3. Re:Bike Frames? by fractoid · · Score: 4, Funny

      Of course, it'll allow manufacturers to gyp 50-year-old men who aren't quite committed enough to their mid-life crises to buy sports cars into paying an extra $2k for Mobius bike frames that shave an extra 200 grammes off the weight of a 6kg bike. These men will then lean said bikes against the railings of expensive snobby coffee shops at 7am and drink coffee while pretending that it's OK to sit around wearing brightly coloured skintight lycra when you're over 50. Sadly, they will never actually realise that the whole point of a 'cafe racer' bike was that it HAD AN ENGINE.

      Also, Mobius bike frames will have the added bonus that they even more easily pretzel into a mobius strip themselves when confronted with a kerb, pot-hole or other such part of the Real World.

      --
      Rampant carbon sequestration destroyed the Dinosaurs' tropical paradise. I'm here to help repair the damage.
  7. The obvious next step by mbenzi · · Score: 2, Insightful

    When they can produce a Klein Bottle I will be impressed. Still not sure either will be be useful, but I will be impressed.

    1. Re:The obvious next step by B1oodAnge1 · · Score: 2, Informative

      But... you can put about a pint into a Klein Stein.

      --
      RUGBYRUGBYRUGBY
  8. Diamonds by gnieboer · · Score: 2, Interesting

    My first thought would be that:
    Carbon Crystal = Diamond

    So handmade custom 'Mobius Diamonds' could be the new rage

    My second though was that
    Carbon Nanotube Crystal != Diamond

    Diamonds are carbon crystals at the atomic level, where is sounds these crystals would be at the molecular level (molecules being bonded groups of atoms)
    So they probably would not share all the characteristics of diamonds. I'd be interested to see what they look like though.

    IANAChemist, so I'm curious to hear from someone more qualified than I about what a nanotube crystal could be like.

    1. Re:Diamonds by Gibbs-Duhem · · Score: 5, Informative

      Well, it will still be made up of graphene when it comes to looking at atomic energy levels. Band gap is the primary source of light interactions, and as it will still be close to zero band gap (unless the asymmetry thrown into long range hybridization screws it up in ways I am not thinking of), and should be absorbing most photons.

      So, it'll probably look the same as graphite, but would probably diffract photons with wavelenghts like 10nm due to it having a longer-range crystal structure than normal crystals (which only diffract in the X-rays). The crystals might do things like diffract in the high energy UV, assuming the UV doesn't all get absorbed by the graphite.

  9. A bit of fact checks. by feranick · · Score: 5, Informative

    Graphene has some pretty interesting electronic properties. Its bandgap (the essential component of all semiconductors)

    Graphene is a semimetal. The bandgap is zero in suspended graphene. Epitaxial graphene on SiC has a small gap (0.1meV) but below Fermi level, so not very useful.

    can be manipulated by changing the length of the sheet; as the sheet becomes infinitely long, the bandgap approaches zero.

    Not correct. The bandgap of a narrow ribbon depends on the width (not the length) of the ribbon. Above 10nm there is no gap, below there is, regardless how long it is.

    As a result, it could hold potential in photovoltaics for light capture or LEDs for light emission where capture/emission is tunable based on the size of the particle (which is pretty easy to manipulate).

    Well, this is totally unrelated as electron-hole pair recombination requires a junction.

    Another article popped up on Slashdot recently suggesting graphene could be used for super high-capacity memory storage: http://hardware.slashdot.org/article.pl?sid=08%2F12%2F18%2F2332251.

    From the paper they mention that active electrons have near-zero effective mass. Since electron mobility is inversely proportional to effective mass, resistivity approaches zero (in essence, we approach superconductivity).

    No. mobility is finite, because you need to take into account of the so called saturation velocity. Besides, near-zero doesn't mean zero, so conceptually the two are completely different.

  10. Ants? by antdude · · Score: 4, Funny

    Will these Mobius strips have ants on them? ;)

    --
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  11. Re:Stable at 500 K? by Anonymous Coward · · Score: 3, Informative

    Water boils at 373K. If you call 127K a "handful of degrees" you are either an american or a retard with really big hands. 500 Kelvin = 226.85 Celsius (water boils at 100c)

  12. Hmm by troon · · Score: 4, Funny

    Article seems a little ... one-sided.

    I'll get my coat.

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