Photos: A surface inspired by geckos
Scanning electron microscope
Here, a scanning electron microscope image of microscopic hairs on a fiber array. The hairs bond with materials that come in contact with them and make a skid-resistant surface.
Another shot of the microarray. The array doesn't provide adhesion. Instead, it's a high-friction surface that prevents an object from falling down. It was inspired by geckos, whose feet provide both adhesion and friction.
That quarter isn't going anywhere. With 42 million fibers per square centimeter, the array (sandwiched between the quarter and the slide) holds the coin in place through van der Waals forces, a bond that forms between two molecules when they are close to each other. Van der Waals forces also keep ice stuck to glass. The array, however, isn't sticky or goopy.
Another shot of the quarter
Another shot of the quarter. It's a lab experiment now, but someday the principles underlying the material could be embodied in products. At a minimum, Carmel Majidi, the grad student who led the study, has a great party trick for the future.