A way to make arbitrarily long nanotubes?

A very interesting article:

Reinforcement of single-walled carbon nanotube bundles by intertube
bridging.
A. Kis1, G. Csányi2, J.-P. Salvetat3, Thien-Nga Lee1, E. Couteau1, A.
J. Kulik1, W. Benoit1, J. Brugger4 & L. Forró1
Nature Materials 3, 153 - 157 (2004)
Published online: 15 February 2004 | doi:10.1038/nmat1076
"During their production, single-walled carbon nanotubes form bundles.
Owing to the weak van der Waals interaction that holds them together
in the bundle, the tubes can easily slide on each other, resulting in
a shear modulus comparable to that of graphite. This low shear modulus
is also a major obstacle in the fabrication of macroscopic fibres
composed of carbon nanotubes. Here, we have introduced stable links
between neighbouring carbon nanotubes within bundles, using moderate
electron-beam irradiation inside a transmission electron microscope.
Concurrent measurements of the mechanical properties using an atomic
force microscope show a 30-fold increase of the bending modulus, due
to the formation of stable crosslinks that effectively eliminate
sliding between the nanotubes. Crosslinks were modelled using first-
principles calculations, showing that interstitial carbon atoms formed
during irradiation in addition to carboxyl groups, can independently
lead to bridge formation between neighbouring nanotubes."
http://intl.emboj.org/nmat/journal/v...12 87838C1#f2
[free full text]

News and Views
Nanotubes: Strong bundles.
Pulickel M. Ajayan1 & Florian Banhart2
Nature Materials 3, 135 - 136 (2004) doi:10.1038/nmat1078
"The mechanical properties of nanotube bundles are limited by the
sliding of individual nanotubes across each other. Introducing
crosslinks between the nanotubes by electron irradiation prevents
sliding, and leads to dramatic improvements in strength."
http://npg.nature.com/nmat/journal/v.../nmat1078.html
[free full text]

The researcher team was able to give bundles of nanotubes nearly the
same strength in bending modulus as individual nanotubes. Individual
nanotubes have a bending modulus of about 1 terapascal. However,
nanotubes merely bundled together don't come anywhere near this
because the nanotubes slide along each other. The researchers were
able to get about 70% of the bending strength of individual nanotubes
in their bundles by inducing bonds between the tubes by electron
irradiation.
Could this work to produce nanotubes of arbitrarily long lengths at
nearly the same tensile strength of individual tubes by using the
electron radiation method to induce bonds between the ends of
nanotubes?



Bob Clark