How do geckos stick to der Waals?

You gape as a little lizard skitters across the ceiling, nervous it might drop right onto your head. But this lizard won’t fall, so just enjoy this wonder of nature’s engineering. The sticky-footed critter above you, better known as a gecko, can adhere to just about any dry surface.

Does this acrobat use suction-cupped feet? Not even close. Geckos have millions of specialized hairs on the bottom of their toes called setae. Each setae splits into hundreds of even tinier hairs called spatulae. On a molecular level, the spatulae and any surface are drawn to one another, like weak magnets. This molecule-to-molecule attraction is known as the Van der Waals force. But since this force is relatively weak, the gecko’s phenomenal grip depends on sheer numbers. Countless rows of spatulae increase the surface area for Van der Waals interactions – a collective attraction that makes the binding force so secure.

In fact, the gecko is more than secure. A single toe, with its millions of ultra-tiny grippers, could support its entire body weight. Scientists are exploring ways to make an artificial gecko-grip inspired by the Van der Waals force. Who knows, maybe we’ll all have sticky feet someday.