Everyone knows geckos have extraordinary powers of adhesion, able to clamber up vertical windows with remarkable ease. With the "Geckskin", a team of scientists have replicated the effect to produce a flat, index-card sized piece of material capable of carrying a 700-pound (318-kg) load - easily enough for a flatscreen television. It can be removed with ease and leaves no unpleasant oomska. And interestingly, it doesn't work as you might think.
Hair today, gone tomorrow
You probably know that a gecko's toes have millions of microscopic hair-like setae that exploit van der Waals interactions that cause attraction and repulsion at the molecular level. Past attempts to replicate gecko superpowers have tended to focus on these setae as a means of making materials adhere, such as
. However, the team of researchers at the University of Massachusetts Amherst discovered that setae are not necessary to solve the problem, being but one part of a gecko's climbing toolkit.
The game's afoot
The research team is mainly comprised of polymer scientists, but also includes biologist Duncan Irschick who has been observing and thinking about geckos' climbing ability for more than 20 years. Taking a more holistic approach to the problem, the team realize that a gecko's skin, bones and tendons work in unison to remarkable and sticky effect.
The Geckskin is a stiff woven fabric incorporating a soft adhesive pad, woven into a "synthetic tendon" like that of a gecko's foot. "Our design for Geckskin shows the true integrative power of evolution for inspiring synthetic design that can ultimately aid humans in many ways," said Irschick. The team is aiming to further improve the Gecksin by looking at the wide variation evident in the evolution of gecko feet.
But the DARPA-funded project is already showing impressive results - with the team demonstrating a 16-square inch piece of material holding up a 42-inch TV - a mere fraction of the 700 pounds it's capable of carrying (the weight of an
, though I don't fancy the Geckskin's chances of withstanding the turning force of an object that size). Impressively, the carrying capacity apparently holds true for glassy surfaces. The Geckskin can apparently be removed (presumably peeled away) with "negligible effort" and can be "reused many times with no loss of effectiveness" which would seem to imply that in its present form the Geckskin does not continue to work at full strength indefinitely.
The team's findings have been published in the current online edition of Advanced Materials.
Sources: University of Massachusetts Amherst, Advanced Materials