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Roll Your Own Nanotubes
March 1, 2012
One of my
uncles used to roll his own
cigarettes. It wasn't for an
aesthetic reason, but because it was cheaper. It's not that manufacturing a cigarette from its component parts is difficult. There was a
huge tax on them at the time, which is much larger now, but a smaller tax on canned
tobacco.
His cigarettes were made on a small, manually-operated machine as you would expect them to be made, by rolling a rectangular sheet of
thin paper along one axis with the tobacco inside. There is, however, another way to make paper tubes, which is evidenced in the thin cardboard tubes that can be found in your household
toilet paper. In those tubes, a much longer sheet is twisted into a
helix until the edges join and are sealed.[1]
Not my uncle's manual cigarette roller.
Figure 1 of US Patent No. 238,640, "Cigarette-Machine," by James A. Bonsack, March 8, 1881.
Not surprisingly, Bonsack was from Roanoke, Virginia
(Via Google Patents).[2)]
That twisting trick appears to be a possible method of using
graphene nanoribbons to produce lengthy
carbon nanotubes. I wrote about nanoribbons of
graphene and
boron nitride in two previous articles (
Graphene Transistors, October 21, 2010 and
Boron Nanoribbons, January 11, 2012).
Computer simulations of this process are reported in a recent issue of
Physical Review B by a team of
physicists from the
NanoScience Center,
Department of Physics,
University of Jyväskylä (Jyväskylä, Finland) and the
School of Engineering and Applied Sciences,
Harvard University (Cambridge, Massachusetts).[3-5]
It's not surprising that carbon nanotubes are easily made, but difficult to make to specification. You get a range of tube diameters and structures. In particular, the way that the carbon units are wrapped, the
chirality, determines whether the tubes are
semiconducting or
metallic.[5]
Graphene, which was originally studied as exfoliated flakes from
graphite, has also been made by
chemically scissoring carbon nanotubes. Perhaps the inverse process is possible; namely, rolling graphene sheets into tubes. If the direction of rolling with respect to the sheet's
crystalline orientation can be controlled, such a process would produce long nanotubes of particular chirality.[5]
The Harvard-University of Jyväskylä team used
quantum molecular dynamic simulations to model the process. Their calculations show that the carbon atoms at the edge of a graphene ribbon will bond to atoms on the opposite edge when the ribbon is sufficiently twisted, thereby creating the nanotube.[3-5] The transformation from sheet to tube proceeds by an intermediate
buckling that's aided by the
elasticity of the
carbon-carbon bond in the graphene sheet.
Rolling a graphene ribbon into a tube. In this example, a ribbon of 38 nm length is formed into a tube by external clamping. It holds its shape after the clamp is removed (lowest figure). Figure 7 of ref. 3 (modified), via the (arXiv Preprint Server))
Although the calculations were for graphene nanoribbons, the method may generalize to other materials, such as the boron nitride that I mentioned earlier.[3,4] It may also simplify the encapsulation of other materials inside carbon nanotubes.[3-5]
These results were from a computer simulation, but how would you do such a thing
experimentally? I would likely attached some
polarizable molecules to the ends of the nanoribbon and use an
oscillating electric field, along with a little
inertia, to snap the ribbons into tubes.
References:
- We know that Wikipedia has a page on just about everything, but even I was surprised by the scholarly article on toilet paper orientation, and the finding in a 1989 survey that "60 percent of those who earn $50,000 or more prefer it to be over and 73 percent of those who earn less than $20,000 prefer under." I prefer my orientation to be over.
- James A. Bonsack, "Cigarette-Machine," US Patent No. 238,640, March 8, 1881
- O. O. Kit, T. Tallinen, L. Mahadevan, J. Timonen and P. Koskinen, "Twisting Graphene Nanoribbons Into Carbon Nanotubes," Physical Review B, vol. 85, no. 8 (February 15, 2012), Document No. 085428 (9 pages).
- O. O. Kit, T. Tallinen, L. Mahadevan, J. Timonen and P. Koskinen, "Twisting Graphene Nanoribbons Into Carbon Nanotubes," arXiv Preprint Server, February 23, 2012.
- Hari Dahal, "Synopsis: Graphene Nanoribbons Zip Up," synopsis of the paper in ref. 2, APS Web Site.
Permanent Link to this article
Linked Keywords: Uncle; cigarette; aesthetic; cigarette tax; tobacco; rolling paper; toilet paper; helix; Roanoke, Virginia; Google Patents; graphene nanoribbon; carbon nanotube; graphene; boron nitride; computer simulation; Physical Review B; physicist; NanoScience Center; Department of Physics; University of Jyväskylä (Jyväskylä, Finland); School of Engineering and Applied Sciences; Harvard University (Cambridge, Massachusetts); chirality; semiconductor; semiconducting; metallic; graphite; chemical reaction; crystalline; Miller index; orientation; quantum molecular dynamic simulations; buckling; elasticity; carbon-carbon bond; arXiv Preprint Server; experiment; polarizability; polarizable; molecule; radio frequency; oscillating electric field; inertia; US Patent No. 238,640.