The Amazing Spider-Man’s web slinging has been a source for research on whether we, the normal two-legged human beings, can climb walls and stand upside down on ceilings. Some animals do it quite well, and scientists have been trying to unravel the mystery behind all those stickiness that helps them gawk from ceilings and walls.
The most sought after superhero of the animal world is the gecko. These little fellows can scamper up walls and ceilings and even hang down on polished glass.
Researches have only unearthed the secret of their sticky power recently. There are millions of microscopic hairs on the underside of the gecko’s feet and each hair is split into hundreds of tips of just 200 billionths of a meter wide.
It’s the weak intermolecular forces, or what researchers call as Van der Waals forces, that draw the materials together when they are close by, causing the adhesion instead of any sticky material that was previously thought to be present. With these forces, the gecko can support its body upside down, and in order to unstick, the gecko pulls its feet at a different angle.
The research behind the gecko’s ability has lead scientists to develop synthetic materials that use synthetic hairs instead of adhesives to stick on to surfaces. The US military has funded a project to develop climbing robots, and Prof Kellar Autumn, who became intrigued by gecko adhesion, has since became engrossed in the mysterious ability.
“What we’re talking about is something that is about as sticky as sticky tape – it’s not crazy glue,” he says. Prof Autumn, along with Mark Cutkosky from Stanford University, using a machine that stimulated gecko climbing, compared natural and polymer-based synthetic gecko hairs.
They found that both the versions could be used again and again, about 30,000 times, without losing their stickiness. Normally, an adhesive tape after re-using a couple of times loses its stickiness.
Synthetic adhesives could be used in robotics, medicine, sports and clothing. But the most widely asked question is whether it will help humans scale walls without the bite of a radioactive spider.
According to physicist and engineer Nicola Pugno from Turin Polytechnic in Italy, we are not far from the day when people could go walking on walls in a Spider-Man suit. He says that if a person dons gloves and boots made from carbon nanotubes that are structured to mimic the gecko’s feet, then the person could safely hang from a wall or ceiling.