Stanford engineers recently demonstrated a pair of gecko-inspired hand pads strong enough to pull the weight of an adult man and to allow him to climb a wall.
The gecko’s clinging ability is due to specialized pads located on its toes, comprised of various satae (bristle- or hair-like structures) on the tip of which lie tiny structures called spatulae, each less than a micron wide. These allow attraction forces called Van der Waals interactions to arise between the adhesive satae and the surface. A single spatulae shows very weak molecular forces, however when coupled together in thousands of thousands on the satae, the attraction becomes very strong.
Researchers created an artificial adhesive that could copy the high surface area of the satae on a gecko’s feet, made from a silicone material called polydimethylsiloxane (PDMS) that is layered as a microscopic wedge. The pads have “controllable adhesion”, so they could easily be switched on or off simply by transferring weight on the adhesive.
The pads could prove useful in manipulating huge solar panels or other massive objects without any suction power or chemical glues, and in space where astronauts could cling to surfaces of the International Space Station.