A team at the University of Manchester, U.K., says it has succeeded in creating a powerful, reusable adhesive tape inspired by the sticky feet of the gecko, the wall-scrambling lizard.
Close-up of bottom of gecko foot.
CREDIT: M. MOFFETT, FROM K. AUTUMN ET AL., PNAS (2002)
Physicist Andre Geim says the feat is based on the principle that almost any submicrometer object--whether a speck of dust or the tip of a single gecko foot hair--will stick to a solid surface because of the weak intermolecular (van der Waals) forces between the two objects. The forces are tiny--just 1/100 billionths of a Newton. (A Newton is 100 grams.) But a dense array of billions of microscopic plastic pillars on Geim's "gecko tape" make a bond so strong that just a palm-sized section would be enough to hang a man from the ceiling, the scientists calculate. The plastic tape itself is flexible enough to allow the pillars to stick to uneven surfaces without clumping, they report in the July issue of Nature Materials.
Bob Full, an integrative biologist at the University of California, Berkeley, who measured the strength of real gecko foot hairs in 2000, says that "uses are nearly unlimited" for a gecko tape: "In addition to a general adhesive, it can be used to move computer chips in a vacuum, pick up small fibers, and design novel bandages."
