MIT Technology Review: Geckos are known for their ability to adhere to and climb vertical surfaces, including sheer ones like glass. They can do so because of the stickiness of their feet, which is due to the weak electrical attraction called van der Waals forces between the surface and the hair-like setae on gecko footpads. Now researchers led by Mark Cutkosky of Stanford University have developed a human climbing system based on the structure of gecko toes. They attached tiles of an adhesive polymer material called PDMS to a flat, hexagonal, hand-sized gripper backed with a spring to distribute the user's weight across the pad. The system allowed a 70-kg graduate student using two of the grippers to scale a vertical glass wall. So far, however, the climbing system has been tested only on very smooth, clean, flat surfaces. If it is to be put to practical use, such as by construction workers for manipulating huge solar panels or by the military for maneuvering in difficult terrain, it will need to be tested under less ideal conditions, such as on wet or dusty surfaces or in zero gravity.
