The process by which carbon nanotubes repair
themselves has now been explained and modeled in detail. These
tubes, sometimes only a nanometer or so in width but microns in
length are among the toughest but also flexible materials known.
And when they develop a tear, whether through irradiation or the
application of extreme heat or strain, they are able to sew
themselves back up without any leftover stitches or imperfections.
The way they do it, a new study conducted by scientists at Rice
University shows, is through the propagation of a sort of sliding
carbon-repair crew. The crew consists of a pentagon-heptagon
phalanx of 10 carbon atoms moving along the tube, filling in the
crack created by ejecting carbon atoms and rearranging local
bondings as they go. The ejected carbons can either go away or they
can be used in the repair work elsewhere (see figure at
Physics News Graphics).
Repair of other
carbon-based material, such as proteins or DNA, is much more
complicated and usually leaves behind stitches or other signs of the
repair. But Rice engineer Boris Yakobson (713-348-3572,
email@example.com) believes that the "5/7 machine" repair mechanism at
work in carbon nanotubes might operate too in other 2-dimensional
tilings, such as micelles (arrays of surface molecules deployed on a
colloid) or microtubules.
Ding et al., Physical Review Letters,
Contact Boris Yakobson
Also see the Rice
University press release