Spider-Man probably inspired more than a few comics fans to imagine walking on walls. Well, take note, superhero wannabes. Cornell University researchers say they've come up with a palm-size liquid-adhesion device that could enable just that sort of arachno-riffic move.
Similar research into adhesion technology has taken its cue from the gravity-defying gecko, but the Cornell team looked elsewhere--to a beetle native to Florida that can stick to a leaf's surface, through wet adhesion, with a force 100 times its own weight.
Observing the beetle's bonding method, which involves applying surface tension across many micron-size droplets, Cornell researchers Paul Steen and Michael Vogel posited that a similar principle could be applied to create load-bearing Post-it-like notes and shoes or gloves for people seeking Spidey-like traction.
The scientists detail their findings in this week's Proceedings of the National Academy of Sciences. Their research was funded by the Defense Advanced Research Projects Agency and the National Science Foundation.
To get a sense of how the device works, think of the way two wet glass slides stick together. Steen and Vogel's silicon wafer device works in much the same way (watch a video demonstration of it here). A flat metal plate with micron-size holes sits atop a plate holding a liquid reservoir. In between is another porous layer. An everyday 9-volt battery pumps tiny droplets of water through to the top layer and the surface tension of the exposed drops makes the device grip another surface.
But what happens when you want to come down from your wall perch? … Read more