Friday, October 31, 2008

From Cool Science Dept: Mimicking Gecko Feet

From AAAS Science Roundup:

"The ability of gecko lizards to scurry up walls and cling to ceilings by their toes has fascinated scientists for decades. The creatures owe this remarkable ability to microscopic branched elastic hairs on their feet that are able to induce atomic-scale attractive forces to strongly grip surfaces. In a Report in the 10 Oct 2008 Science, Qu et al. reported on the latest attempt to mimic this impressive adhesive effect. The team showed that a disordered array of vertically aligned carbon nanotubes -- consisting of a straight body segment with curly entangled tops -- can achieve macroscopic adhesive forces almost 10 times that of a gecko foot. A strong shear adhesive force, forged when the tangled portions of the nanotubes become aligned when pressed onto a surface, allows for a strong grip of vertical surfaces without slipping, while a much lower normal adhesive force enable easy removal and reattachment. In addition to the ability to stick objects to walls, the material could have many technological applications, including connecting electronic devices and substituting for conventional adhesives in the dry vacuum of space."

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