Gecko lizards explain

Jun 15, 2007 07:32 GMT  ·  By

Nature prevails over human technology in many cases.

Gecko lizards have amazed people for long with their ability to walk on walls and ceilings. The secret behind this amazing ability lies on an unique quick-release mechanism that permits geckos to strongly adhere to a surface, but then detach with ease, unlike conventional adhesives that either adhere weakly and detach easily (like Post-it notes) or are strong and hard to remove (like duct tape).

Researches on the geckos' adhesive ability, coming from [admark=1]sticky hairs (setae) covering the lizards' toes, could lead to the development of advanced glues.

A team led by Keller Autumn, a biologist at the Lewis & Clark College in Oregon, US, measured the force needed to detach hairs from a surface, and how that force changed, depending on the angle of appliance. When the force bends the hairs at an angle of about 30 degrees to the horizontal, they can stand huge forces.

"Geckos are vastly over-engineered. One gecko could resist the weight of 130 kilograms." said Autumn.

When the angle is changed over 90 degrees, the hairs can be easily detached. As the hairs are solid, they are not harmed in this process and can be employed repeatedly.

"It's such a bizarre solution to an engineering problem. No one would have ever thought of it if it hadn't evolved in geckos." Autumn told New Scientist.

Gecko adhesive could be used one day in car braking systems.

"It could stop a car traveling at 80 km per hour in a distance of just 5 m, using just one third of a square meter of the substance."

Synthetic gecko feet have been developed for small robots, but application in cars could wait more.

"Scaling things up creates big problems. We know it's a challenge none of the virtual gecko adhesives are capable of doing." said Autumn.

He hopes that nanotechnology, based on strong carbon nanotubes and silicon nanowires, could turn this into a reality within the next 10 years.

"So far, no one has managed to create great sheets of this stuff. Nanotubes are grown from vapor disposition - it's a very delicate process with high temperatures." said Peter Forbes, who examined similar applications of nanotechnology.

Photo Gallery (2 Images)

This gecko is hanging upside down
Pulling the Gecko hair in one direction causes it to stick tight (b), but applying a force at a larger angle allows it detach with ease (a)
Open gallery