The remarkable characteristics of advanced materials are often reported in terms of their superhero potential. One common example is a category of adaptable, mechanical adhesives that are designed to perform like a gecko's feet. Early news stories about these materials imagined humans being able to scale glass walls with lizard-like hands—a capacity straight out of comic books. Although most materials are never tested for such real-life use, engineers at Stanford University are actively exploring the option.
According to a recent Stanford press release, "If you spot someone stuck to the sheer glass side of a building on the Stanford campus, it's probably Elliot Hawkes testing his dissertation work.” Hawkes (shown above) and his mechanical-engineering colleagues are putting the long-promised capability of synthetic gecko feet to the test with his custom-fabricated, handheld pads.
Like the reptile's toes, each pad's surface is covered in sawtooth-profiled microstructures that are approximately the width of a human hair. When the pads initially touch a smooth material such as glass, they do not adhere readily. When force is applied, the sawtooth forms rotate into contact with the surface to form a strong bond. Because the material uses springs that become more flexible as they are pulled, the pads can be easily repositioned once the force is removed.
What’s it like to climb the outside of a glass curtainwall? Said Hawkes in the press release: "You keep expecting to slip off, and when you don't, it surprises you. It's pretty exhilarating."
In a video demonstrating the technology in application, Hawkes climbs slowly and employs a harness for safety. Nevertheless, the proof-of-concept material that emulates a naturally occurring technology to give humans so-called superhero capabilities works, with potential future applications in construction including robot-installed curtainwalls and skylight systems.
Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.