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Search for ideal adhesive leads to fake gecko feet
Team reports the synthetic hairs have 200 times the sticking power made by nature
By DENISE GRADY
New York Times
The scientific quest to make artificial gecko feet has taken a leap forward.
Geckos, lizards that are notorious for their sticky feet, can run up walls and across ceilings, and hang tauntingly by one toe. They have no suction cups, hooks or glue on their feet, so how do they do it?
Five years ago, researchers at the University of California at Berkeley, Stanford University and Lewis & Clark College found the secret: About 500,000 minute hairs cover the sole of each foot, and the tip of each hair splits into hundreds more. The hairs are so elastic that they can bend or squish to conform to microscopic nooks and crannies under the creature's feet, even on the glass walls of an aquarium
As a result, the tiny hairs touch so much surface area so closely that weak forces of attraction between molecules in the hairs and in whatever surface the animal is walking on add up and become sufficient to let the gecko hang on. The connection breaks when the gecko shifts its foot enough to change the angle between the hairs and the surface.
The discovery intrigued scientists who immediately realized that if synthetic gecko-foot hairs could be made, they might be a great adhesive — strong, glue-free, dry, reusable and, unlike suction cups, capable of working in a vacuum such as that of outer space.
The National Science Foundation gave a $400,000 grant to scientists at the University of Akron and Rensselaer Polytechnic Institute to try to make imitation gecko feet. In a recent issue of the journal Chemical Communications, the team reported that it had indeed produced synthetic hairs, with 200 times the sticking power of the ones made by nature.
Although the scientists have tested only minute amounts of the material, they estimate that if its properties hold up on a larger scale, a dime-size patch of it could support 2 to 22 pounds, depending on how densely the hairs were packed.
The synthetic hairs — one-ten-thousandth the width of a human hair — are made of highly flexible carbon cylinders, or nanotubes, embedded in a plastic base like bristles in a hairbrush.
http://www.davesdaily.com/out.php?id...izarre/3337724
By DENISE GRADY
New York Times
The scientific quest to make artificial gecko feet has taken a leap forward.
Geckos, lizards that are notorious for their sticky feet, can run up walls and across ceilings, and hang tauntingly by one toe. They have no suction cups, hooks or glue on their feet, so how do they do it?
Five years ago, researchers at the University of California at Berkeley, Stanford University and Lewis & Clark College found the secret: About 500,000 minute hairs cover the sole of each foot, and the tip of each hair splits into hundreds more. The hairs are so elastic that they can bend or squish to conform to microscopic nooks and crannies under the creature's feet, even on the glass walls of an aquarium
As a result, the tiny hairs touch so much surface area so closely that weak forces of attraction between molecules in the hairs and in whatever surface the animal is walking on add up and become sufficient to let the gecko hang on. The connection breaks when the gecko shifts its foot enough to change the angle between the hairs and the surface.
The discovery intrigued scientists who immediately realized that if synthetic gecko-foot hairs could be made, they might be a great adhesive — strong, glue-free, dry, reusable and, unlike suction cups, capable of working in a vacuum such as that of outer space.
The National Science Foundation gave a $400,000 grant to scientists at the University of Akron and Rensselaer Polytechnic Institute to try to make imitation gecko feet. In a recent issue of the journal Chemical Communications, the team reported that it had indeed produced synthetic hairs, with 200 times the sticking power of the ones made by nature.
Although the scientists have tested only minute amounts of the material, they estimate that if its properties hold up on a larger scale, a dime-size patch of it could support 2 to 22 pounds, depending on how densely the hairs were packed.
The synthetic hairs — one-ten-thousandth the width of a human hair — are made of highly flexible carbon cylinders, or nanotubes, embedded in a plastic base like bristles in a hairbrush.
http://www.davesdaily.com/out.php?id...izarre/3337724
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