43 innovations

Artificial gecko coating

If engineers could create a material that matches the nimble lizard's incredible grip, we could make super-grip shoes for athletes and tyres that hold the road better in all weathers, for example. The hairs on a gecko's feet - called setae - are the key to its remarkable grip on just about any surface, rough or smooth, wet or dry. The tips of the setae are so sticky that geckos can hang from a ceiling with their entire weight suspended from a single toe.Two microscopic polymer bumps, roughly the same size as those on a seta, have the same sticking power as a gecko hair. Although, individually, these forces do not amount to much, millions of them combine to produce the gecko's impressive sticking power.Now an engineer called Metin Sitti at Carnegie Mellon University in Pittsburgh, has created some polymer-based setae. They are not yet strong enough to hold an adult human on a ceiling, but they are slowly getting there. Right now, Sitti says, they can stick things weighing a few kilograms to a ceiling, but the synthetic gecko hairs are still being improved.To replicate gecko hairs, says Sitti, you need to recognise the importance of their shape and orientation. It is not enough to cover a flat surface with lots of bumps: they have to make contact with the tiny bumps in a surface to exert a useful attractive force.

Source: newscientist.comAdded: 5 March 2007