PORTLAND, Ore. -- Spiderman-like suits that allow the wearer to scale vertical walls are possible, according to Professor Nicola Pugno at the Polytechnic University of Turin, Italy. Real spiders, it turns out, use capillary and van der Waals forces--the molecular attraction between very small objects--to keep the tiny hairs on their legs attracted to the molecules of a wall. Sticky synthetic suits, according to Pugno, could likewise harness capillary and van der Waals forces, as well as custom designed nanoscale forces strong enough to suspend a person on a wall or even hang them from a ceiling.
Pugno's formula for such a Spiderman suit uses a nanofabricated version of the natural form of adhesion used by spiders and geckos. Nanostructures can be etched that exploit the same capillary forces arising when a thin layer of water sits between a hair and a surface. Massive numbers of extremely small touch points elicit the same van der Waals force of attraction between the hairs on a spider's legs and those of the climbing surface. The researchers also recommend a nanoscale version of Velcro--a carbon nanotube-based material formed into molecular-sized hooks and loops.
Pugno claims that the necessary lightweight, ultra-strong material could be made by weaving millions of 10-nanometer thick carbon nanotubes into threads about one centimeter thick with their ends splayed out, fan-like, to maximize contacts and, thus, stickiness. By combining capillary, van der Waals and velcro-like mechanical forces, a carbon nanotube thread could hold the weight of a man, according to Pugno.
Pugno's cookbook, called "Towards a Spiderman suit: large invisible cables and self-cleaning releasable super-adhesive materials" has been published online.