新普京娱乐网址:Gecko's gravity-defying trick explained

作者:危膦    发布时间:2019-03-01 05:17:11    

By David Robson (Image: Journal of the Royal Society Interface) The secret behind the gecko’s extraordinary wall-climbing ability is a unique quick-release mechanism that allows it to adhere strongly to a surface, but then detach with ease. Researchers in the US say that the mechanism could be used to make advanced glues or even car braking systems. Geckos get their adhesive ability from sticky hairs – called setae – that cover the lizards’ toes. But the stickiness is unlike conventional adhesives, which either adhere weakly and detach with ease like Post-it notes, or are strong and hard to remove like duct tape. By contrast, gecko hairs adhere strongly and detach easily. To find out what makes this possible, Keller Autumn, a biologist at the Lewis & Clark College in Oregon, US, and colleagues measured the force required to detach hairs from a surface, and how that force changed according to the angle at which it is applied. When the force causes the hairs to lie at an angle of about 30 degrees to the horizontal, they can resist enormous forces. “Geckos are vastly over-engineered,” says Autumn. “One gecko could resist the weight of 130 kilograms.” At angles of over 90 degrees, however, the hairs easily became detached. And because the hairs are solid structures, they are not damaged in this process and can be used repeatedly. Autumn told New Scientist: “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.” Gecko adhesive is so effective that he believes it could one day find use in car braking systems. He calculates it could stop a car travelling at 80 kilometres per hour in a distance of just 5 metres, using just one third of a square metre of the substance. While synthetic gecko feet have been created to hold small robots, though, researchers are still a long way from being able to use the material in cars. “Scaling things up creates big problems,” said Autumn. “We know it’s a challenge none of the virtual gecko adhesives are capable of doing.” Nevertheless, he believes that with the development of strong carbon nanotubes and silicon nanowires that could used instead of gecko hairs, a comparable adhesive could become a viable option within the next 10 years. Peter Forbes, author of The Gecko’s Foot, which examined similar applications of nanotechnology, shares Autumn’s reservations: “So far, no one has managed to create great sheets of this stuff. Nanotubes are grown from vapour disposition – it’s a very delicate process with high temperatures.” However, he believes that at least four teams, including one from British Aerospace, are working towards similar, although smaller applications, of the material. “I’m certain the use of ‘gecko materials’ will be possible, but no one knows when it will happen.” Journal reference: Journal of the Royal Society Interface (DOI:


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