BMW -- Plan to Design a Nano-Car

Windscreens that no longer steam up, or paint that no longer gets dirty or can be scratched: all this could be everyday reality for car drivers in just a few years time. As part of their research work, engineers at the BMW Group are examining the use of nanotechnology in future cars. The range of possibilities is large. Currently the company is working on an agent that will counter dirt and paint damage, and small nanoparticles are of great help in this.

Purchasing a new car in 2020 - the scenario: the showroom dealer, in addition to exhibiting BMW's latest shiny new models, also sets up a stand with small, colourful seed packets. The packets, however, do not have pictures of exotic plants printed on them but instead car models. The customer chooses a car, pays for it, and is then handed over his dream car in a seed packet. He scatters the seed in his garden and waits, and at some point, just like a flower, his dream car sprouts up from the earth. Atom by atom, molecule by molecule.

What today seems like science fiction could tomorrow be reality. This is because there is no reason why objects cannot be created on an atom by atom basis, the proof for this being provided as far back as 1959 by American physicist and Nobel prize winner, Richard Feynman. In 1986 US researcher Eric Drexler too prophesied that: "In the future programmable molecular-sized robots will be able to grab hold of individual atoms and place them at the exact location where we want them to be. We will be able to replicate each new object atom by atom, be it a strawberry or a car." Just one year later the first step in this direction was taken when the decisive tool for conquering the atomic world was discovered. Since then scientists have been able to precisely design and mix the building blocks of the universe. Also possible now is the construction of artificial molecules which can be used as minute machines - almost exactly as Drexler prophesied.

Drexler and Feynman are considered the intellectual fathers of nanotechnology. To some extent it is a dwarf science, as "nanos" in Greek means "dwarf", and a nanometre in physics corresponds to one billionth of a metre or one millionth of a millimetre.

The number of uses that can be made of nanotechnology in the car industry is enormous. Take, for example, scratch-free windscreens: If one mixes silane, large molecules made of silicon, metal and alcohol groups, with water, these convert into silanols, which in turn develop into blobs several nanometres in size. Chemically elongated molecules can be attached to these, the ends of which contain the chemical element, fluoride, familiar because of its use in toothpaste. If one removes the water from this mix, referred to as "sol", the blobs form an unbroken network.

"In this way a viscous gel is created", explains BMW's nano-expert, Dr. Michael Nikolaides. If this gel is then applied to vehicle surfaces, the molecules with their fluoride heads behave on the open surfaces in accordance with the laws of thermodynamics. "It is this layer of fluoride ends that makes it hydrophobic - like in the case of a Teflon frying pan", explains the nano-expert. The characteristics of these coatings offer considerable advantages: The coating is transparent and can be applied as clear lacquer over the paint on the vehicle body. Furthermore it can be water-resistant, so that dirty water does not dry into a layer of dirt on it. This lotus flower effect, also called "easy-clean", allows water to trickle down more easily and makes it almost impossible for dirt to latch on to paint. The BMW Group is carrying out research into this effect, which is called "hydrophobing". Water, when it comes into contact with the fine nanostructures on the leaf surfaces of the lotus plant, trickles down very easily and takes all the dirt with it. This is also the idea behind special nano paints; graffiti created using such paints can be wiped off as easily as chalk from a blackboard. "One disadvantage of such artificial coatings up until now has been their lack of permanence, as artificial coatings, in contrast to plants, do not grow again", explains Nikolaides.

Using nanotechnology the paint on a vehicle could even be designed as a solar cell, although this has yet to be realised. The electricity generated from such a cell while the vehicle was stationary could be used to recharge the battery or to cool the inside using a heat pump. This is still a long way off, however. Help with air-conditioning is provided in the form of windscreens that incorporate nano-scale components, which, depending on the current applied, increase or decrease the rate of light and thermal radiation. Even today vehicle light is produced using nanotechnology, with the LEDs of high-quality braking lights equipped with nanometre-scale layer systems that convert electricity into light more efficiently. Another plus point: LEDs convert electricity directly into light visible to the human eye, whereas braking lights and light bulbs take a little longer to do this. This difference can represent several metres braking distance. By now the intensity of LEDs is so high that grouped together they can create the dipped beam of front headlights.