While it's not Spider-Man-worthy -- yet -- researchers at Cornell University have developed a new adhesive device that could one day let humans hang from and scale walls. The research was published online this week in the Proceedings of the National Academy of Sciences.
The device consists of flat plates patterned with tiny holes. A nine-volt battery pumps water through the device, causing droplets to squeeze through. The tension created by the droplets causes the device to grip another surface, similar to the way two wet glass slides will stick together.
"While our calculations suggest that our device could hold the weight of a human being, climbing walls is quite a different story," said Michael Vogel, the study's lead author. "There would probably be some serious safety issues to consider." But, he added, work on the device will continue -- and it will examine the potential uses for humans. "The immediate and obvious directions are tackling the issues involved in transforming the prototype into a device that could literally hang us from the ceiling," Vogel said.
The key finding in the report about the device, which was also written by Paul Steen, deals with scaling, Vogel said. "As the holes on the device are made smaller, we can pack even more of the holes into a square inch, and the strength of the device will increase dramatically," he said. "We can extrapolate from our data that a square inch device could hold 15 pounds or more."
In the meantime, the device has other potential applications. Robots could use it to stick to ceilings or walls, Vogel said, or it could simply hang items around the house.
What's next for the research team? The device is just one example of an application that relies on their concept of a "droplet switch," in which the shape or position of liquid droplets can be controlled, Vogel said. "We'd also like to explore other areas, like using the droplets to create real-time morphing/transformer-like materials, or for locomotion, or even applications in medical devices," he said.
Photo: Adhesion device holding its own weight, plus Lego figure, against Plexiglass/Courtesy of Michael Vogel