The war continues—a battle for the ages. Which side will win—arachnids and other insects with sticky feet, or the slippery slopes of passive carnivorous plants like the pitcher plant?
Actually, materials scientists who study both sides are the real winners.
Human beings have spent a lot of time looking for perfectly frictionless surface coatings; writers like Clifford Simak and Frank Herbert have imagined them in science fiction. Just as the stickiest surfaces have been found on the feet of natural creatures like geckoes and spiders, slippery surfaces have also been found in the natural world.
Researchers from the Max Planck Institute for Metals Research and the University of Hohenheim have shown that the carnivorous pitcher plant uses an especially slippery slope to catch prey. The plant has a lid, a peristome (a ring around the trap entrance), a slippery zone and a digestive zone.
The plant walls of the slippery zone are covered with a double layer of crystalline wax. The upper layer has crystalloids which contaminate the attachment organs that insects use to adhere to surfaces. It is made of single, irregular 30-50 nanometer platelets standing more or less perpendicular to the plant wall.
The lower layer is similar to foam, being made of connected membrane-like platelets which stick out at sharp angles and offer no clear orientation. This layer further reduces the contact area between insect feet and plant surface.
Writing in Way Station, a Hugo-award winning 1963 novel, Clifford Simak imagined an absolutely impenetrable and frictionless coating:
It was as if the knob was covered with some hard, slick coating, like a coat of brittle ice, on which the fingers slipped without exerting any pressure on the knob...
He tried a thumbnail on it, and the thumbnail slipped but left no mark behind it... The rubbing of his palm set up no friction...
(Read more about the frictionless surface)
Read about water repellent glass modeled on lotus leaves to find out more about a successful instance in which real-world material science was able to imitate nature. On the other side of the coin, take a look at a scientific investigation of the sticky feet of spiders. Read more about howPlants provide new ideas for anti-adhesive surfaces.
(This Science Fiction in the News story used with permission from Technovelgy.com - where science meets fiction.)