Scholars have long marveled at the superlative climbing abilities of gecko lizards. But only recently have scientists figured out how the creatures manage their gravity-defying feats. As it turns out, the sole of the gecko foot is covered with millions of submicron hairs that apparently stick the animal to the substrate by way of intermolecular van der Waals forces.
Nanotechnologist Andre K. Geim of the University of Manchester and his colleagues set out to create a novel type of adhesive mimicking the gecko's gripping mechanism. Their prototype--which consists of an array of microfabricated polyimide hairs attached to a flexible base (see image above)--exhibits an adhesive force per hair that is comparable to that of a gecko foot-hair. And the flexible base ensures that as many hairs as possible come into contact with the substrate. Because the adhesive is dry, it can be attached and detached repeatedly.
So far, Geim and his collaborators have made only a small amount of gecko tape--one square centimeter, to be exact--owing to manufacturing cost and difficulty. That was enough to suspend a Spidey action figure from a pane of glass (see image at left). But the researchers' calculations show that if they had enough to cover a human palm (200 square centimeters or so), gecko tape could support the weight of an average person.
