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Ultra-Strong Nanotube Composites
TheMatt writes "In a story that makes you say "Cool!", Nicholas Kotov and co-workers have
created a nanotube composite material six times stronger than carbon-fiber composites. Their final product is a crosslinked material which appears to be just as strong as silicon carbide and tantalum carbide!"
Materials have the following attributes (and others of course):
Now, stiffness is one of the important ones. High Young's modulus (stiffness) good, low Young's modulus bad. Stiff and light is better; stiff, light and tough really attracts attention.
For a very readable introduction to this, I recommend The New Science of Strong Materials (or why you don't fall through the floor) by J.E. Gordon, also his Structures.
Protoplasm. Quiet Protoplasm. I like quiet protoplasm.
(or at least, "data *I* can't understand) can be found by following the "references" link at the bottome of the linked page.
It lead me to a nature.com, where, after registering with them (and opting out of EVERYTHING, which was easy), I read the Far More Technical nature article. It went way over my head.
WAY over:
"
The mechanical properties of the layered composites were tested on a custom-made thin-film tensile strength tester (McAllister) recording the displacement and applied force by using pieces cut from ((PEI/PAA)(PEI/SWNT)5)6 and ((PEI/PAA)(PEI/SWNT)5)8 freestanding films. The tester was calibrated on similar pieces made from cellulose acetate membranes and nylon threads. ((PEI/PAA)(PEI/SWNT)5)6 and ((PEI/PAA)(PEI/SWNT)5)8 samples had an average thickness, measured by TEM, of 0.75 and 1.0 m respectively.Their typical stress ( ä) versus strain ( å) curves differed quite markedly from stretching curves seen previously for SWNT composites10 and for LBL films made solely from polyelectrolytes, (PEI/PAA)40, obtained by the same assembly procedure (Fig. 4b). They displayed a characteristic wave-like pattern,a gradual increase of the d ä/d åderivative, and the complete absence of the plateau region for high strains corresponding to plastic deformations (Fig. 4a).The latter correlates well with the enhanced connectivity of SWNT with the polymer matrix (Fig. 2).
"
And that's the relatively clear stuff. I could actually follow some of it. Yow!
Fooz Meister
Alas, there is still a long way to go before space elevators can be built.
The strength of this material will be suffice for space "tethers" that can work as slings to catapult loads into higher orbits, or even give them escape velocity.
Genuine space elevators require a strength several orders of magnitude greater, but the maximum strength of individual nanotubes makes it theoretically possible to get there.
For details, see an article in American Scientist (NOT Scientific American) 5-7 years ago. It discussed the minimum strength required, and the reasons carbon nanotubes just might work.
Ironically, Buckminster Fuller, the discoverer of Buckminsterfullerene (carbon nanotubes can be seen as tubular extensions of these molecules), was a friend of Arthur C. Clarke, the author of the first space elevator novel "The Fountains of Paradise".
Neither Fuller nor Clarke suspected that Fuller's discovery one day might serve as the foundation to high-strenght materials that could make space elevators possible !
Yours Birger J.
Ironically, Buckminster Fuller, the discoverer of Buckminsterfullerene ...
R. Buckminster Fuller did not discover Buckminsterfullerene.
Buckminsterfullerene was named after him because it resembles a geodesic dome, which R. Buckminster Fuller invented.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Anybody have any more information or links that explain how flexible this new material is?
Yup. If the nanotubes are chemically bonded to the matrix, as the article suggests, and it is comprised of 50% nanotubes, it would be extremely stiff. Far stiffer than any carbon fiber composite.
As far as flexibility of a physical shape (thread, cable) goes, anything is flexible if it is thin enough that opposite faces don't develop significant compressive/tensile stresses on bending. This is one reason why most cables are a bundle of smaller wires/threads. (Reliability is another issue, since if one goes it doesn't take the others out with it, as would happen if a cable was a solid piece of material (e.g., metal)). You can bend a multifilament line easily, whereas a solid cable of the same diameter would either be too stiff to bend easily, or would break or permanently deform as a result of the bending.
So, tethers or cables made from these nanocomposites would most likely be multifilament, making them flexible enough to be spooled easily, while still being very strong.
The Buckminsterfullerene (or buckyball) was not discovered by Buckminster Fuller. It was created by a graduate student in Dr. Richard Smalley's Lab at Rice U., after astrophysics professor Harold Kroto in the UK wanted to collaborate with him regarding the process of carbon nucleation (Smalley's experiment provided a nice approximation to deep space conditions).
The name Buckminsterfullerene was picked because Richard Buckminster Fuller created the geodesic dome, which is essentially what a half of a buckyball looks like.
Following the buckyball's discovery, people all over began to create other things: different-sized buckyballs, bucky-ears, bucky-heads, and the famous buckytube. The buckytube gradually became renamed "nanotube" and that's where we are today!
JoeRobe
The best way to predict the future is to invent it.