I don't how I missed this back in 2008 or perhaps I saw they were not as strong as nanotubes in tensile strength so I din't pay much attention to them, but a team in 2008 announced development of what they refer to as "colossal carbon tubes" which they say are stronger than carbon nanotubes on a per weight basis:
Aug 8, 2008
Carbon nanotubes, but without the 'nano'.
http://physicsworld.com/cws/article/news/35364Specific strength.
http://en.wikipedia.org/wiki/Specific_strengthPeng, H.; Chen, D.; et al., Huang J.Y. et al. (2008). "Strong and Ductile Colossal Carbon Tubes with Walls of Rectangular Macropores". Phys. Rev. Lett. 101 (14): 145501. doi:10.1103/PhysRevLett.101.145501
http://www.mse.ncsu.edu/research/zhu/papers/CNT/PRL-CCTs.pdf [full text]
The reason the team says the colossal carbon tubes have higher specific strength than carbon nanotubes is because while their tensile strength is 7 GPa, just slightly better than carbon fibers, their density is only 0.116 g/cm³(!)
Schematic illustration of a colossal carbon tube. (Credit: Huisheng Peng, LANL, et al.)
These tubes so far are only centimeter lengths but another quite useful aspect of them is their large diameters compared to nanotubes, in the range of 50 to 100 microns. This would make them much easier to work with as far as combining them together to create longer lengths.
Bob Clark
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