Working at Lewis & Clark College, the University of California at Berkeley, the University of California at Santa Barbara, and Stanford University, the interdisciplinary team: * confirmed speculation that the gecko’s amazing climbing ability depends on weak molecular attractive forces called van der Waals forces, * rejected a competing model based on the adhesion chemistry of water molecules, and * discovered that the gecko’s adhesive depends on geometry, not surface chemistry. In other words, the size and shape of the tips of gecko foot hairs—not what they are made of—determine the gecko’s stickiness. To verify its experimental and theoretical results, the gecko group then used its new data to fabricate prototype synthetic foot-hair tips from two different materials. “Both artificial setal tips stuck as predicted,” notes Autumn, assistant professor of biology at Lewis & Clark College in Portland, Ore. “Our initial prototypes open the door to manufacturing the first biologically inspired dry, adhesive microstructures, which can have widespread applications.” Please Register or Log in to view the hidden image! Geckos have millions of setae—microscopic hairs on the bottom of their feet. These tiny setae are only as long as two diameters of a human hair. That’s 100 millionth of a meter long. Each seta ends with 1,000 even tinier pads at the tip. These tips, called spatulae, are only 200 billionths of a meter wide—below the wavelength of visible light. Intermolecular forces come into play because the gecko foot hairs split and allow a billion spatulae to increase surface density and come into close contact with the surface. This creates a strong adhesive force,” says Autumn. A single seta can lift the weight of an ant. A million setae, which could easily fit onto the area of a dime, could lift a 45-pound child. If a gecko used all of its setae at the same time, it could support 280 pounds gecko Why van der Waals? Although they are the weakest type of intermolecular force, they are ubiquitous and occur between all types of surfaces. This means that the key to dry adhesion is the shape or geometry of the adhesive, rather than the chemistry. Other insects which stick by secretions (e.g. ants, beetles, flies, etc.) are much more picky about what types of surfaces they stick to. Geckos can stick to any surface, with the exception of Teflon, which was specifically engineered to prevent even van der Waals adhesion. (You might say that Teflon is the Anti-Gecko.) Dry adhesives such as these have evolved independently multiple times within gekkonid lizards, as well as in anoles, skinks, and multiple times again in spiders. This highly diverse set of organisms allows us to conduct statistically powerful comparative studies to determine how adhesive feet evolved and what benefits they confer on the animals which possess them. anne peattie
Is that true Clockwood? Would these gloves be able to support the wearer..for instance, in climbing a wall? Geckos rock. I forget where they're native too (australia maybe??) but where they live they run around in people's homes and eat bugs. Pretty nice neighbors if y ou ask me
I dont know if they would support a wearer on a smooth surface alone but if the person could grip something even a little i think it would work. After all, people have been known to climb up the sides of buildings without any equipment. I ame sure it would help considerably. I am not making this up.
The clincher was creation of synthetic split ends that stick almost as well as the real spatulae of Tokay geckos. With the help of an atomic force microscope to punch wax molds of the right size, Fearing cast little spatulae of two separate materials - silicone rubber and polyester resin. He then used the microscope to measure the adhesion force of these rubber feet. "One bump at the end sticks with 200 nanoNewtons of adhesive force," at least half of which is due to van der Waals forces, Fearing said. "We confirmed that it's geometry, not surface chemistry, that enables a gecko to support its entire body with a single toe." A nanoNewton is the weight of a single blood cell, that is, the force exerted on a blood cell by Earth's gravity. The force exerted by sunlight on a satellite orbiting the Earth is on the order of 200 nanoNewtons. Since fabricating the initial nanobumps, Fearing and post-doctoral fellow Metin Sitti have found a way to make arrays of 10,000 rubber bumps. Though the centimeter-square arrays don't yet adhere to surfaces better than rubber without bumps does, the team sees this as proof of concept. "We can apply the underlying principles and create a similar adhesive by breaking a surface into small bumps," Fearing said. "These preliminary physical models provide proof that humans can fabricate gecko glue." Added Full, "We've shown directly that something manufactured out of different materials works by the same mechanism proposed for gecko toe hairs. We think that the deformable nature of these tiny tips, and perhaps the whole hair, allow you to get very close to any kind of surface. That's the http://www.berkeley.edu/news/media/releases/2002/08/26_gecko.html
That post was in 2002. Do we have the gloves out in the market yet? Please Register or Log in to view the hidden image! I saw some magazine that had socks rather than gloves for astronauts in space stations so that they could walk.
that quote by anne peattie seems to be referenced only in sci this is a reason why i have always felt that quoting text (partial or in entirety) is not necessarily a bad thing tho thats true peattie there is the pdf Please Register or Log in to view the hidden image! or maybe it is this pdf Please Register or Log in to view the hidden image! Please Register or Log in to view the hidden image! peattie2
