Soon we'll have special gloves and shoes that allow us to climb smooth, vertical surfaces — and even walk across ceilings. A team of researchers at UC Berkeley has created a plastic microfiber that imitates the "stickiness" of gecko feet, which are covered in tiny hairs that attach to smooth surfaces. Already, the researchers are predicting they'll be able to walk robots across the ceiling using their microfibers, and humans could be next.
A release describing the new microfiber explains:
Taking a cue from the millions of hairs covering a gecko's toes, researchers squeezed 42 million hard plastic microfibers onto each square centimeter of material and loaded it with various weights. They found that on a smooth, clean, vertical surface, two square centimeters of the synthetic adhesive could hold 400 grams (0.88 pounds). At the same time, the adhesive easily lifts off with minimal force and no residue . . . Previous research on gecko-like adhesives has focused on the strength of the adhesion . . . However, that the ease of attachment and detachment are equally important when developing a material that can practically be used for scaling vertical walls and ceilings.
What sets this new gecko-inspired adhesive apart from the others created thus far is that it is directional, only "sticking" when it slides along a smooth surface, not when it is pressed down. "This difference is critical because if you're climbing up vertical surfaces, you can't afford to use a lot of energy pressing down into the surface to stick," said [UC Berkeley EECS professor Ron] Fearing. "Using force to attach also requires force to detach. A gecko running uphill may be attaching and detaching its feet 20 times a second, so it'd get very tired if it had to work hard to pull its feet off at every step." The microfibers, made of polypropylene, are 20 microns long, or one-fifth the thickness of a sheet of paper, with a diameter of 0.6 microns, or one-hundredth the diameter of a human hair.
Ah, perfect for scaling those mirror-skinned buildings that are ultrasmooth.
New Adhesive Mimics Gecko Toe Hairs [Eurekalert]