Geckos are known for their incredible ability to hang onto almost any surface. From glass to wet paint, these small lizards can keep themselves firmly in place, that is with the exception of one surface; Teflon.
Teflon, also known as PTFE or tetrafluoroethylene, is the nonstick coating most often found in cookware though it has many other applications. Researchers at the University of Akron found that it’s the one surface that a gecko cannot stick to. There is one caveat to this, however. The surface coated with Teflon must be dry. When the researchers placed the Teflon surface underwater, a gecko had no problem staying put using its amazing adhesive ability. But how do geckos stick to almost any surface where another animal would simply slide off?
The answer lies in the incredible properties of the gecko foot. A gecko has five toes on each foot, and on each of these toes are thousands of microhairs. These microhairs don’t actually stick or press down to the surface a gecko is walking on. They drag against the surface instead. The hair is at an angle coming from the gecko’s toe which allows it to stay in position, but when it needs to move, the gecko simply moves in the opposite direction to free the toe from the surface.
The researchers at the University of Akron also found that when a gecko is faced with a wet surface, tiny air pockets are created by the geckos’ toes which allow them to stay dry and safely planted to whatever material they are on. In addition, the footpads on a gecko are self-cleaning which enables the lizard to walk over a dirty surface and not slip off.
This may all seem like interesting trivial information, but it does have important real-world applications. Learning how a gecko’s foot manages to stay “sticky”, especially in water, is leading to the development of adhesives that stick while being applied in water or have improved sticking properties. Imagine a robot that can crawl across almost any surface, tape that can be used in construction, or being able to apply a bandage underwater and not have it fall off, just to name a few. All this and much more could be possible with understanding how a gecko moves across almost any surface without falling off.