Inspired by the agile gecko's uncanny ability to run up walls and across ceilings, researchers at Rensselaer Polytechnic Institute and the University of Akron have been successful in creating a synthetic "gecko tape" with four times the sticking power of the real thing.

According to Pulickel Ajayan, the Henry Burlage Professor of Materials Science and Engineering at Rensselaer, and Lijie Ci (a postdoctoral research associate in Ajayan's lab):

"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.

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 compliance.

Geckos inspired us to develop a synthetic gecko tape unlike any you'll find in a hardware store. 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 researchers described in a paper published in the June 18-22 issue of the Proceedings of the National Academy of Sciences 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.

Find more details from the full report.

[In photo: Microfabricated aligned multiwalled carbon nanotube setae and spatulas. (A) Optical picture of gecko foot showing that the setae are arranged in many lobes along the foot. (B) SEM image of natural gecko setae terminating into thousands of smaller spatulas. (E-H) SEM images of synthetic setae of width 50 (E), 100 (F), 250 (G), and 500 (H) µm. (C and D) Side views (C) and higher Magnification SEM image (D) of the 100 µm setae. Credit: University of Akron.]