University of Massachusetts Amherst scientists have discovered just how a gecko's sticky feet work - and created a 16-inch-square device that can stick a 700-pound weight to a wall.
"Amazingly, gecko feet can be applied and disengaged with ease, and with no sticky residue remaining on the surface," says biologist Duncan Irschick.
Previous efforts to mimic this have been based on the qualities of microscopic hairs on geckoes' toes called setae, and have been pretty successful - but only on a small scale.
Trying to scale it up failed, partly because the complexity of the entire gecko foot - including tendons, bones and skin - wasn't taken into account.
But the Massachusetts team's new Geckskin shows that setae aren't actually necessary.
"It’s a concept that has not been considered in other design strategies and one that may open up new research avenues in gecko-like adhesion in the future," says Alfred Crosby.
The trick was to create an integrated adhesive with a soft pad woven into a stiff fabric, which allows the pad to 'drape' over a surface to maximize contact. Further, as in natural gecko feet, the skin is woven into a synthetic 'tendon', helping maintain stiffness and rotational freedom, the researchers explain.
Importantly, the Geckskin’s adhesive pad uses simple everyday materials such as polydimethylsiloxane (PDMS), which holds promise for developing an inexpensive, strong and durable dry adhesive.
"Our design for Geckskin shows the true integrative power of evolution for inspiring synthetic design that can ultimately aid humans in many ways," says Irschick.