The tiny pads on the soles of geckos' feet have inspired a super-adhesive strong enough to hold up a car, according to U.K. researchers.

Credit: istockphoto

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SYDNEY: A doormat-sized piece of a new, ultra-adhesive material is so strong that it could suspend the weight of a family car, according to researchers.

Called Synthetic Gecko, the glueless material could be used for instant repair patches for damaged structures - such as fuel tanks - as well as in the manufacture of super-grip tyres and many other applications.

Scientists at BAE Systems, England, created the artificial surface that grips incredibly tightly without adhesive solutions or pressure. The sticky surface is inspired by the gecko - a reptile whose ability to scurry up vertical glass panels and walls has intrigued people for centuries and inspired comic-book characters such as Spider-Man.

"We wanted to mimic this ability," said Jeff Sargent, research physicist at BAE Systems' Advanced Technology Centre. "We recognised that a synthetic material could have tremendous engineering potential not only in our own aerospace and defence businesses but also in other commercial applications."

The gecko gets its ability to stick without glue from the soles of its feet, which are patterned with millions of tiny hairs with split ends. At the tip of each split is a mushroom-shaped cap less than a 1,000th of a millimetre across. These caps maximise foot surface area in very close contact with the surface, and allow molecular attraction to make the gecko 'stick' to the surface. The grip is released by a peeling action when the animal lifts its foot.

Using micro-engineering clean-room facilities, BAE Systems' scientists, led by Jeff Sargent and Sajad Haq, created layers comprising thousands of microscopic stalks with splayed tips, closely resembling the mushroom-headed hairs on a gecko's feet.

Future applications could include an adhesive to repair aircraft, skin grafts - and even create a Spider-Man-style 'suit' with super sticking power.

"It would mean that a window cleaner could dispense with his ladders and climb up the side of your house," explained Haq. "There's a whole host of applications. It's just a question of your imagination."

Synthetic Gecko is the latest in a series of materials to draw inspiration from the nimble reptiles, since the mechanism behind their amazing powers was described by Univeristy of California scientists several years ago.

Geckos utilise molecular forces called van der Waal's forces, which arise when electrical charges around molecules attract one another. The cumulative attractive force of billions of hairs allows geckos to run up vertical windows and walls and even hang upside down on polished glass.

Synthetic Gecko is made by a modified version of a technique known as photolithography, commonly used to make silicon chips. The technique uses light to etch three-dimensional patterns into a material.

"The processes we use are modifications of standard electronic fabrication processes," said Haq. "They are cheap, well known, well understood and can be scaled up to very large areas cheaply."

The next step in the development program comprises further research into the influence of surface roughness and water on the adhesive properties of the material, to ensure that it is effective on a range of surface roughness.