Published online:
22 October 2003; | doi:10.1038/news031020-5
Super-strong
adhesive planned with hooked carbon strands.
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Normal nylon velcro has hooks and
loops, nano-velcro will be all hooks. ©
SPL | |
Nano-velcro could hold objects together
as tightly as a strong adhesive, say US researchers1.
The reusable
material is carpeted with hook-ended carbon tubes, each just
millionths of a millimetre across. It could fasten components in
ultra-small robots, propose David Tománek and colleagues at Michigan
State University in East Lansing.
The researchers estimate
that nano-velcro would be about 30 times stronger than conventional
epoxy adhesives. It would bond most solids together so powerfully
that the materials themselves would break before the pads of hooks
came apart. It would also be about 3,000 times stronger than a
microscopic version of Velcro made by carving tiny hooks into
silicon wafers2.
Tománek's
team calculates that two hooks can straighten out enough to be
pulled apart if yanked sufficiently hard, but that they spring back
into place, unharmed, once separated. When pushed back together, the
hooks link up again.
The energy stored as the hooks bend while
separating heats them to around 1,000 °C when they spring back into
place. But nanotubes are robust enough to withstand this without
breaking, and are very good at conducting heat away from their
ends.
Unfortunately, no one has yet found a way to grow carbon
nano-hooks en masse routinely. Individual ones were first created
nearly ten years ago, and some researchers have managed to grow
entire forests of them, but not to order.
References
- Berber, S., Kwon, Y.-K. & Tománek,
D. Bonding and energy dissipation in a nanohook assembly.
Physical Review Letters, 91, 165503,
doi:10.1103/PhysRevLett.91.165503 (2003). | Article | ChemPort |
- Han, H., Weiss, L. E. & Reed, M. L.
Micromechanical Velcro. Journal of Microelectromechanical
Systems, 1, 37 - 43, (1992). | Article |
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