Close(r), but no cigar…

When I first read this article, my thoughts were “Wow!  Has the ribbon problem finally been solved?”  The specific line that made me think this was;

“Now, a research team from Northwestern University in Evanston, Illinois, has assembled particles of graphene oxide, a form of graphite and a cousin of diamonds, into very thin sheets that ARE EVEN STRONGER THAN THOSE OF THE [CARBON] NANOTUBES.”  (emphasis mine)

But wait, how can this be?  I thought carbon nanotubes were theoretically the strongest material possible.

Then the article said;

“Laboratory tests showed that the grapheme paper was as strong as that made from carbon nanotubes…”

Wait.  First its “even stronger”, then its “as strong as”.  ???  I guess they’re picking and choosing what kind of carbon nanotubes to compare it with (and then changing that on the fly).

The accompanying abstract gave some real numbers to look at; the strength of this new graphene oxide paper is given as 32 GPa.  Very strong indeed, nearly 8 times as strong as steel, but, alas, not strong enough for an earth-based Space Elevator (130 GPa needed for a factor of two safety margin – Edwards).

Still, a very impressive accomplishment indeed.  If/once the water solubility issue is solved, this stuff will be used in all sorts of applications.  They could even make mail envelopes out of it; lets see the post office try and mangle those…

(Photo credit: Northwestern University.  Click on it or visit the articles to view a larger version)

Update July 29th – I’ve heard from a couple of people that not all GPa’s are the same, and that this stuff isn’t that strong at all.  Please note Tom Nugent’s comment on this post…

3 thoughts on “Close(r), but no cigar…

  1. Tom Nugent

    Sorry to burst your bubble, Ted, but it’s the elastic modulus which is reported as being 32 GPa, not the strength. The tensile strength is reported as ~120 MPa, which is lower than vermiculite and is comparable to some copper alloys. It’s more than an order of magnitude below the best current materials.

    The research is nevertheless interesting. It’s just not strong stuff.

  2. Ted Semon Post author

    Yeah, Tom, Andy Price said much the same thing in an email he released. But the author of the article said the stuff was “stronger than carbon nanotubes” so at least I had a partner in crime 🙂

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