For years, researchers have been fascinated with the mechanism of adhesion that allows geckos to efficiently climb and scale vertical surfaces. Since its initial discovery, various synthetic dry adhesives have been developed to allow humans to mimic the same ability – unfortunately, to no avail. Now, thanks to a new study published in the Journal of the Royal Society Interfaces, scientists have figured out the secret: they have developed a new technology that will give Spiderman a run for his money.
The innovative pair of hand pads will essentially allow users to scale glass walls, just like a gecko. The adhesive equipment is made from a silicone material called polydimethylsiloxane (PDMS) that is layered as microscopic wedges. Although the material isn’t actually sticky, it is capable of gripping onto slippery surfaces thanks to the laws of physics.
But how does it work?
Essentially, the grip relies on van der Waals forces – or the attractive/repulsive forces between molecules. Although weak, they can be powerful when utilized correctly. Geckos, for example, take advantage of these forces through a system of tiny, branched hairs, known as setae. These nanoscale fibers, located on their toes, can be attached and detached to make contact with even the roughest surfaces. This results in millions of contact points that are distributed evenly to carry the gecko’s weight.
Thus far, the biggest puzzle in replicating this ability involves the actual adhesive. Most manmade ones are capable of sticking only once, and become difficult to release afterward. A gecko, on the other hand, can easily lift its leg, shift its weight and stick again.
This new technology, however, will allow users to exhibit “controllable adhesion” that can be switched on or off by transferring weight to the adhesive. Thus, the hand pads create a nearly uniform load distribution, and could potentially be used for various practical applications. The technology, for example, may be useful to astronauts grabbing debris in space.
For more information on the findings and the technology, check out the Journal of the Royal Society Interface.
Video demonstration of hand pads, courtesy of YouTube.
