Tree-Frog Feet Inspire Super-Sticky Tape

Now here's a sticky situation. How do you make a tape that doesn't lose its grip when it is peeled off and reused?

Tree frogs, crickets and some other animals have mastered the problem. So researchers in India thought they ought to be able to figure it out too, and they did, they report in Friday's issue of the journal Science.

Researchers led by Abhijit Majumder at the Indian Institute of Technology in Kanpur, India, studied the toe pads of tree frogs to figure out what makes them stick to surfaces, and copied the idea.

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When conventional sticky tape is pulled off of a surface, cracks spread through the adhesive away from the point where the tape is being detached.

This makes it possible to peel the tape, but the cracks remain and are part of the reason it loses its stickiness.

The researchers found that a pattern of tiny channels on the frogs' foot pads increased their adhesion to a surface, while the channels prevented the spread of cracks when the feet are pulled from surfaces.

They then designed elastic layers embedded with channels filled with either air or fluids beneath an adhesive layer.

The result: stickiness increased by as much as 30 times, and the material could be peeled off and reused.

The research was supported by the Indian Institute of Technology and the Department of Science and Technology of India.