Tough Enough

 

Being only one ten-thousandth the thickness of a human hair, yet displaying structural properties akin to those of diamonds, carbon nanotubes are heralded as the biggest of the little things that are set to revolutionize the world. These tiny hollow cylinders made from sheets of hexagonally-arranged carbon atoms could be ideal for use in applications including synthetic muscles, artificial nerve systems that may serve as smart sensors, high-performance car bodies and bridges, as well as novel electronic devices.

What makes them so appealing is that according to theoretical calculations, nanotubes should have incredible mechanical properties – close to the absolute best – rendering them the strongest, hardest, stiffest, toughest material ever to exist. So incorporating these nanotubes into other materials to make composites should greatly enhance those materials’ properties. “But their infinitesimal size makes it hard to prove this experimentally,” explains Prof. Daniel Wagner of the Weizmann Institute of Science’s Materials and Interfaces Department.

 

Together with his postdoctoral fellow Lu-Qi Liu from China, Wagner developed unique methods for creating nanocomposites and probing their mechanical properties. Their method, based on the so-called electrospinning technique, involves injecting the nanotubes into nanofibers in a parallel fashion and then twisting the strands of nanofibers into a microrope structure. They achieved this by attaching the nanofibers to a rotating motor that weaves the strands in a way similar to children dancing with ribbons around a maypole. The results, recently published in Advanced Materials, show that the nanocomposites turn out to be extremely tough.