When I was a child, Spiderman was my favorite comic character. I loved the way he crawled on vertical walls of buildings. I used to ponder how I could do that. But look at gecko they do it every day all the time. Geckos virtually can stick their feet on any surface and climb up any surface.
Many scientists are intrigued by the way these animals manage the feat. Although these scientists are not willing to become Spidermen they want to make self cleaning adhesives. They have been trying to know how a gecko manages to stick itself to any thing but at the same time it also repels the dirt clinging on to its own feet. If something is sticky then it should become covered with layer of dirt after some use. Isn’t it? Then how is that gecko’s foot are always clean? Gecko never grooms itself.
To know the secret Dr. Kellar Autumn, a biologist at Lewis & Clark College and an author of the study looked very closely at gecko’s feet. He studied the hair structure and has now to a large extent solved the mystery.
He observed that the creature’s foot has millions of minuscule hairs, or setae, with tiny pads at their tips. The setae are not more than 200-billionths of a meter wide. These tiny structures can cover tiny contours of any surface. The surfaces of the setae and of the support attract each other due to weak van der Waals forces. Since gecko has millions of these tiny hairs the combined strength of the force is enough to lift up to 250 pounds of weight. At the same time geckos individual setae attract dirt with a weaker force than that of the underlying surface. Thus gecko manages to lose dirt as it walks around.
So what does it means to us. It can mean a lot depending on where the newly acquired knowledge is applied. Dr Kellars study shows that the adhesive effect is due to the geometry of the hair and not due to its chemical composition. This means that it won’t be difficult to manufacture adhesive tapes that mimic gecko’s feet. Since the adhesive effect is due to the structure of the hair the tape could be made from any material. The chemical nature of the tape does not matter much. Maybe we can have self cleaning, reusable duct tapes.
Dr Kellar has even envisaged applications in NASA's rover. Rovers using the geckos trick could manage to reach difficult to climb areas like huge rocks on Mars.
