Response from: Richard Jones

I'm going to side with the fossilised faculty member on this one... the elastic modulus of a material doesn't actually depend much on configuration, because it's basically set by the density of bond energy of the material. Strength, though, is a different issue. That's why the modulus of carbon nanotubes isn't so different to the modulus of ordinary carbon fibre (carbon fibre typical modulus is 230 GPa, nanotubes maybe a bit more than 1000 GPa) - the number of SP2 carbon-carbon bonds per unit volume is pretty similar. They can in principle be very much stronger, though, (200 GPa against 3.5 GPa), because strength really comes from how perfect the structure is. On the other hand, this also means that the strength deduced from a single nanotube in a microscopic experiment is likely to be very different (much bigger) from the strength you'd achieve in a nanotube rope. Nanomaterials are very exciting, but they don't rewrite the rules of materials science.

Response from: Richard Jones

But, despite my last comment, your general point - that there's a lot of conservatism about about materials choice, is certainly true.

Response from: George Elvin

Thanks, this is one of the best things about a blog - the opportunity to learn and discuss. No one in our faculty meeting had the expertise to debate the details of nanotube elasticity, but when you reach out through the internet, you instantly get global debate and global learning.

Response from: DrugDetox

Well my opinion is that faculty member just couldn't get beyond the conventional wisdom that materials have inherent, unalterable properties we have no control over. Conservative, conventional viewpoints like his will make life interesting for anyone looking to implement new nanomaterlals with unconventional properties in the marketplace.