Nanotube Adhesive Sticks Better Than a Gecko’s Foot
Troy, N.Y., and Akron, Ohio — Mimicking the agile gecko,
with its uncanny ability to run up walls and across ceilings,
has long been a goal of materials scientists. Researchers at
Rensselaer Polytechnic Institute and the University of Akron
have taken one sticky step in the right direction, creating
synthetic “gecko tape” with four times the sticking power of
the real thing.
In a paper published in the June 18–22 issue of the
Proceedings of the National Academy of Sciences, the
researchers describe a process for making polymer surfaces
covered with carbon nanotube hairs. The nanotubes imitate the
thousands of microscopic hairs on a gecko’s footpad, which form
weak bonds with whatever surface the creature touches, allowing
it to “unstick” itself simply by shifting its foot.
For the first time, the team has developed a prototype
flexible patch that can stick and unstick repeatedly with
properties better than the natural gecko foot. They fashioned
their material into an adhesive tape that can be used on a wide
variety of surfaces, including Teflon.
Pulickel Ajayan, the Henry Burlage Professor of Materials
Science and Engineering at Rensselaer, and Lijie Ci, a
postdoctoral research associate in Ajayan’s lab, created the
material in collaboration with Ali Dhinojwala, professor of
polymer science at the University of Akron, and University of
Akron graduate students Liehui Ge and Sunny Sethi.
“Several people have tried to use carbon nanotube films and
other fibrous structures as high-adhesive surfaces and to mimic
gecko feet, but with limited success when it comes to realistic
demonstrations of the stickiness and reversibility that one
sees in gecko feet,” Ajayan said. “We have shown that the
patchy structures from micropatterned nanotubes are essential
for this unique engineering feat to work. The nanotubes also
need to be the right kind, with the right dimensions and
“Geckos inspired us to develop a synthetic gecko tape unlike
any you’ll find in a hardware store,” Dhinojwala says.
“Synthetic gecko tape uses ‘van der Waals interactions’ — the
same interactions that hold liquids and solids together — to
stick to a variety of surfaces without using sticky glues.”
The material could have a number of applications, including
feet for wall-climbing robots; a dry, reversible adhesive in
electronic devices; and outer space, where most adhesives don’t
work because of the vacuum.
The research was funded by the National Science
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