Tree-frog inspires new super glue

An Australian green tree frog uses its suction-cup toes to climb up a glass window at the Taronga Zoo in Sydney November 23, 2004.

HONG KONG (Reuters) - Inspired by the toe pads of tree frogs and crickets, researchers in India have created a form of sticky coating that is both strong and reusable.

When conventional adhesive tape is pulled off a surface, cracks form on the tape, which also picks up dust and other particles, quickly losing its stickiness.

Writing in the journal Science, the researchers described how the toe pads of tree frogs contain "microscopic channel patterns" that stop cracks from forming.

"Toe pads have patterns on the surface, it's not a smooth layer. Underneath these patterns, there are fluid vessels, glands and blood vessels," said Animangsu Ghatak, an assistant professor at the Indian Institute of Technology in Kanpur.

"Sticky tape gets contaminated with dust and you only use it once or twice. But lizards and toads use their toes all the time. They don't get contaminated and they create very strong adhesion. We are trying to mimic that by creating this material."

Ghatak and his colleagues added tiny fluid vessels in their model adhesive and found they increased adhesion by 30 times.

"These fluid vessels, because of the capillary pressure, the adhesion stress increased by 30 times," Ghatak said by telephone.

The team hopes to use their technology on stickers for utensils and food so that they may be peeled off cleanly, and on other adhesive devices that are meant to be reused.

"One application is for stickers on utensils, fruit, where you want to remove them cleanly, you don't want the adhesive to remain on them, which is annoying," he said.