1 of 2 10/15/2007 10:45 AM
Monday, June 25, 2007
Climbing Walls with Carbon Nanotubes
A new kind of tape mimics the qualities of gecko feet.
By Kevin Bullis
Researchers have developed a carbon-nanotube-based tape that could prove useful for
creating robots that climb walls and special adhesive gloves for astronauts. Unlike
ordinary tape, which eventually loses its stickiness, this new material sticks like a
permanent glue, but it can be removed and reused. It can also stick to a wider variety of
materials, including glass and Teflon.
Dubbed "gecko tape" by researchers, the material works by imitating the nano- and
microscale structures on geckos' feet that allow them to quickly scale walls and run
across ceilings. The tape is reusable and will not dry up or slide off the wall because,
unlike ordinary tape, it does not use viscoelastic glues. Instead, it employs carbon
nanotubes to make use of microscale van der Waals forces that occur at very short
ranges between surfaces. Bundles of nanotubes conform to the slightest microscopic
variations on a surface, the same way that the bundles of nanoscopic keratin fibers that
make up the hairs on gecko feet allow them to conform to walls.
Like ordinary tape, gecko tape clings strongly when pulled parallel to a surface; it can