Gripit, gripit ......how the tiny tree frog's sticking power inspired a new supertape

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Gripit, gripit ......or how the tiny tree frog's sticking power inspired a new supertape

By LIN JENKINS - More by this author » Last updated at 23:28pm on 24th November 2007 Comments
It has long been one of nature's marvels: how tree frogs support their body weight upside-down on tiny sticky feet.
But now scientists have used the design of the creatures' toe pads to create a super-sticky tape that is an incredible 30 times stronger than normal.
And by copying the way the pads function, the new tape can also be peeled off cleanly and used time and time again.
Scientists who have made the breakthrough believe the new kind of adhesive will have a wide range of uses.
Not only could it spell the end of having to scrape infuriating labels off newly bought items, but it could also function as a reusable super-adhesive coating – for example on gloves where maximum grip is crucial.

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King of the clingers: The super-adhesive tree frog

Normal tape loses its stickiness when pulled off a surface because tiny cracks occur in the adhesive. But the scientific team at the Indian Institute of Technology in Kanpur have overcome this cracking by recreating the microscopic channels found in the toe pad of a tree frog.
The frog's channels also contain an adhesive mucus, so the scientists have filled their adhesive's cracks with fluid.
The result is that surface tension draws an object and the tape together like a sponge soaking up water.
Yet, remarkably, the tape can also be pulled off without leaving a residue and can be reused.
One of the team who worked on the project, Animangsu Ghatak, said: "In the animal world the mechanism of adhesion has evolved for millions of years and is very elegant."
"With a single foot these animals not only create an adhesion strength 50 to 100 times their own body weight, but also allow very quick debonding when required."
"Furthermore, these adhesives do not get contaminated by dust or particulate matter, unlike most man-made adhesives."
He added that his team could now develop a tape that was 30 times stronger than existing sticky tape.
Dr Ghatak said: "In this new adhesive we trap a viscous liquid inside channels made of elastic material. So overall the adhesive remains elastic and comes back to its original form after use."
"While liquid inside the channel supplies adhesive strength, bulk elastic material gives it reusability."
Jon Barnes, who studies tree frog adhesion at the University of Glasgow, said that in future nature would provide more models for developing technology.
He added: "In this area of science, taking design ideas from nature is certainly coming of age."