London, October 11 : Chinese and American researchers have discovered a new carbon material that is potentially lighter and stronger than conventional carbon fibres.
Huisheng Peng and his colleagues at Shanghai-based Tongji University have found that a carbon vapour made by heating ethylene and paraffin oil can condense into tubes of pure carbon, tens of micrometers wide and up to several centimetres long.
The researchers say that individual tubes have a tensile strength greater than that of conventional carbon fibres, and that they show ductile behaviour just like metal wires when pulled.
They believe that the spongy carbon tubes could be used for making high-strength fabrics for body armour and engineering, which would be better than Kevlar fibres currently used for super-strong cables and bulletproof jackets.
"This is a new form of carbon that was unexpected to me," Nature magazine quoted Mildred Dresselhaus, a specialist on carbon technology at the Massachusetts Institute of Technology, Cambridge, as saying.
The spongy structure, coupled to the intrinsic lightness of carbon, gives the tubes an extremely low density.
Porous forms of carbon have been made before, but not in this fibrous form. The porous tubes also conduct electricity rather well, and thus can find uses in flexible 'textile electronics'.
The researchers are yet not clear as to how the carbon atoms organize themselves into such complicated structures.
However, they suggest that the spongy walls form first as flat sheets, which then gradually curl up and ultimately meet edge to edge to form cylinders.