Geckos exploit weak attractive forces to hold on to glass.
|A gecko on a glass shows the finger structures used to hold on.|
Geckos, small reptiles found in Africa, Asia and Europe, have evolved one of the most powerful mechanisms of adhesion to walls, glass and any other surface. Even Aristotle had noticed their extraordinary ability. For a long time, however, how they managed to climb on the glass remained a mystery. A group of researchers from some universities in Oregon and California revealed the secret. The millions of small hairs that dot the gecko's expanded fingers use, due to their adhesion to each surface, a weak molecular attraction, called the van der Waals force, which acts only when two substances are in contact. The very small "thirsts" present on the surface of the feet adhere one by one with minimal force; but since they are millions and millions, the result is a very high adhesive power.
New hills. According to the researchers, it would be possible to create a kind of "superfast", with tiny silks like those of geckos, which have a comparable adhesive power, and a large number of possible applications.
(News updated 10 September 2002)