Inspired by the toe pads of tree frogs and crickets, scientists at the Indian Institute of Technology, Kanpur, have developed a super-sticky reusable adhesive.
Conventional tape cracks when it is pulled off a surface. The cracks enable removal, but usually also render the tape useless for reapplication.
The toe pads of tree frogs and crickets, on the other hand, contain microscopic channel patterns that prevent cracking.
Lead study author Abhijit Majumder and his colleagues have now embedded the same type of micro-channels in the new adhesive, which thwarts cracks.
Study coauthor Animangsu Ghatak said that during their research, they also found they could increase the adhesive strength by partially filling the micro-channels with fluid.
The scientists report in their study in the journal Science that the surface tension of the liquid creates a capillary effect -- the ability of one substance to draw another toward it like a sponge soaking up water.
In this case, the elastic adhesive pulls tighter to the surface to which it is attached, increasing its stickiness, they said.
According to the scientists, the combined properties of the micro-channels and fluids increase surface adhesion of the elastic material by about 30 times.
"You get stickiness without getting stickiness -- in the sense that you get a sticky material that doesn't leave anything behind," said Anand Jagota, an adhesion scientist at Pennsylvania's Lehigh University who was not involved in the study.
"It captures the physics rather than... the actual structure," he said.
Ghatak said though they have now created a piece of adhesive large enough to hold only a cover slip on a microscope slide, the tape can be made bigger and used in several applications.
"For example, the tape could be used to help baseball and cricket players keep their gloves on, or to keep price tags on supermarket goods. Another potential use is for the feet of wall-climbing robots," National Geographic quoted him as saying.
