Water can make geckos lose their grip

Science : In their search for a better adhesive, scientists have been studying geckos, which are well known for their ability to stick to surfaces. But as Alyssa Stark of the University of Akron in Ohio and colleagues found out , the lizards’ grip is significantly reduced in the presence of water. Geckos’ feet have tiny hairlike structures called setae, each split into hundreds of nanosized tips called septulae. The van der Waals interactions between the molecules of the lizards’ septulae and the molecules of the surface underfoot are so strong that geckos’ sticky toe pads can support the weight of two humans. There are limitations, however. When they get their feet soaked and are placed on a wet surface, geckos exhibit a significant reduction in adhesive ability. Scientists are studying the effect in order to come up with the ideal adhesiveâmdash;reusable, super strong, and water-resistant.