American Association for the Advancement of Science
Stickier than gecko feet
If you've ever seen a gecko scale a wall, you know that these little lizards can climb anything. Geckos can even hang from a ceiling by one toe, thanks to tiny little hairs with "split ends" on their foot pads that give them their super cling. Now, wouldn't it be great to get some of that gecko glue power to stick up a poster on a wall, or maybe paste together two pieces of metal or glass?
University of Dayton engineer Liangti Qu and fellow researchers wondered if they could match the gecko's design with one of their own. They built a sticky layer of nanotubes -- tiny carbon threads -- packed together and standing upright like a microscopic forest. Then they topped their forest with a curly tangle of nanotubes, to look more like the gecko foot hairs. They tested their nanotube tape on a bunch of different surfaces, including glass, sandpaper and plastic films.
So how did it work? The nanotube tape is tough -- it's ten times stronger than a gecko's foot when it comes to sticking and not sliding down a vertical surface like a wall. But like the lizard's nimble toes, it can be easily pulled off a surface when it's time to move on. This is kind of the best of both worlds for an adhesive, the researchers say -- super-sticky but also easy to remove.
This research appears in the 10 October issue of Science.