Rutronik News

Natural genius

  Newsletter Article

Nature is still the best inventor. Researchers discover new and fascinating attributes among our flora and fauna every day and try to put them to good use for humans. One of the best known examples is the lotus effect: Due to the unique surface structure of the lotus leaves, water droplets simply roll off, taking dirt particles and fungal spores with them.

This was discovered back in the 1970s by Wilhelm Barthlott, emeritus professor of botany and bionics at the University of Bonn. And even though he has retired, Barthlott is not at all tired of researching - just like his physicist colleague John B. Goodenough, whose search for an alternative to the lithium ion battery we reported on last year.

The field of bionics was still in its infancy when Wilhelm Barthlott started to conduct research. Even the publication of his article in a US magazine was dismissed with the words: "The so-called lotus effect exists solely in the fantasy of its discoverer." Nowadays, products that are manufactured on the basis of the surface structure of the lotus are used in around 600,000 buildings all over the world. He is now possibly on the trail of the next big thing: Salvinia. This seemingly unremarkable floating fern possesses an extraordinary attribute. Even though Salvinia moves around on and beneath the water, it doesn't actually come into physical contact with it.

The ingenious aspect of it is that the plant creates an air cushion as a result of its surface structure. This prevents it from coming into contact with water and allows it to breathe even under water. The fern has very fine, water-resistant hairs on its surface that create the air bubble. Yet that in itself isn't too spectacular, because water spiders also create an air bubble around them, although not permanently. Salvinia is able to do this, however. And this has specific benefits for the shipping industry. Thanks to the considerably lower frictional resistance, scientists from the Karlsruhe Institute of Technology (KIT) calculate that up to 30 percent less fuel will be needed. In theory, this could save up to 73 million metric tons of fuel on the high seas - equivalent to a cut in CO2 emissions of 300 million metric tons or approximately a third of the annual emissions produced by the Federal Republic of Germany.

However, it is not just this discovery that has huge potential: Humankind is also putting other evolutionary achievements to good use in a number of different ways. In Zimbabwe's capital Harare, for example, there is a multifunctional building called the Eastgate Centre, whose ventilation system is based on that found in a termite mound. The humidity and temperature on the inside of the mound are constant - thanks to air exchange. Cool air enters the structure and warm air is forced out by opening and closing certain ventilation shafts. The Eastgate Centre also works on the same principle: The warm air is released through chimneys in the evening and at night, while cool air from the lower floors rises and cools the building. At the same time, the walls and windows are designed to absorb as little heat as possible from the sunlight.

Equally fascinating is slime mold, which helps to model the ideal transport network. This is not a joke: Japanese scientists placed slime mold on a subway map of Tokyo and then positioned an oat flake on each point of the map where a station is located. The slime mold initially began to grow in all directions, but as soon as it found an oat flake, it optimized its feeding routes to establish a link to the food source before continuing to grow. At the end of the experiment, the growth of the slime mold almost exactly replicated Tokyo's subway network.

Not had enough yet? We have one more for you: How often have you cursed your adhesive tape, because it hasn't stuck properly and the parcel that you thought was securely sealed suddenly opens and its contents spill at your feet? Or notes and other things simply fall from the wall because the adhesive tape is unable to cope with the huge weight of an A4 sheet of paper? Here, too, researchers have turned to nature for solutions - or to the feet of geckos, to be more precise. The feet have a large number of very small hairs that are able to penetrate a surface at microscopically small irregular points, giving the gecko a huge contact area and allowing it to utilize the weak cohesion forces that hold materials together. Researchers are now attempting to imitate this ability by producing an adhesive tape that not only sticks 100 percent reliably, but can also be peeled off without losing this ability. This would undoubtedly be a heavy blow for the adhesive tape industry and writers of rom-coms in equal measures - after all, they would be robbed of one of their most popular gags.

In any case, we would love to have gecko feet, because it would ultimately mean that we could soon clamber up the side of buildings vertically like Spiderman. We still need to work out what use this would be, but at least we could utilize the saying: "I could climb the walls!"