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More than just paint

Marque, model, motor and then the exterior finish – choosing the right car always includes selecting the right paint.

But it’s not sufficient for the paint just to look good. How about a coat of paint that repairs itself, never gets dirty, and changes its color when asked? In the future paint will grant our every wish.

What’s my color?

Neuropsychologists, designers and advertising managers have long been trying to draw conclusions about customers’ psychology from their individual color preferences. White is chosen by conscientious, orderly drivers, while the owners of green cars are calm and silver stands for prestige and elegance – so it is said. However, preferences of drivers in Germany tend not to vary much and most often they choose the darker shades. According to Germany’s Federal Motor Transport Authority, in 2018 around 55 percent of all newly registered cars were either gray or black. And the big, wide world is no more colorful. The Global Automotive 2018 Color Popularity Report found that last year, 37 percent of new passenger cars rolled off the production lines painted white, while black cars accounted for 18 percent, and silver and gray made up 12 percent each.

„Give a child a piece of paper, some colored pencils and ask him to draw a car, he is sure to make it red.“

Enzo Ferrari (1898 - 1988)

Sports cars are not particularly important for representative statistics, but here personal color choices are completely different. The aim is to get noticed, whatever it takes. Mango, Alubeam or eggplant – anything goes. Of course Ferraris are always red. And there is another color that is inextricably associated with the DNA of the prancing horse: yellow – the color of Modena, the home town of Enzo Ferrari and the cradle of the Italian car cult. And ever since Don Johnson drove a white Ferrari Testarossa in his role as Detective James Crockett in the TV series Miami Vice, white has also been accepted by fans and does not immediately lead to a considerable loss in value when the car is re-sold. But the color rosso corsa is most reminiscent of Grand Prix races in days gone by when racing cars were painted a certain color depending on their country of origin to make them more easily distinguishable. British cars had green bodywork (British racing green) – the old traditional color for Jaguar and Land Rover. French racing cars were blue, and their German counterparts were initially white, and later silver in color, which gave rise to the nickname “Silver Arrow”.

Rosso Ferrari – red is the lifeblood of the Italian sports car maker. Picture: Unsplash, Marc Kleen
Rosso Ferrari – red is the lifeblood of the Italian sports car maker. Picture: Unsplash, Marc Kleen

Painting marathon

The paintwork is ultimately only around 0.1 millimeters thick – little more than a human hair. There are four layers of paint in total, from primer and surfacer to basecoat and clearcoat. First of all, the bodywork is cleaned in a dip tank. After a phosphate coating, the bodywork undergoes a process called cathodic electrodeposition to protect it against corrosion. Then the layers of paint are applied. Robots cover the bodywork with surfacer, basecoat and clearcoat. The surfacer, also known as primer, is a second layer offering protection against stone chips and UV radiation. The basecoat provides the desired color. The clearcoat is a final shield that seals and protects all the layers below. At the same time it creates a glossy finish.

The entire procedure takes several hours, during which the vehicle passes through several driers the size of a garage. For the final check it then enters a light tunnel equipped with either fluorescent tubes or LED modules so that even the tiniest unevenness will show up. Audi has expanded the process for special models in the R8, TT and Q2 series by adding an innovative individualization stage. The top layer of paint is slightly abraded and roughened to create matt lettering, logos or motifs on the surface.

No flaw can slip past the LED technology in the innovative light tunnel, according to vehicle-maker Eisenmann – Copyright: Eisenmann
No flaw can slip past the LED technology in the innovative light tunnel, according to vehicle-maker Eisenmann – Copyright: Eisenmann

Nano paints – from color to function

Once a car takes to the roads, the painted surface very quickly loses its shine. Heavy rain, kiddies’ fingers, carwashes and shopping trolleys on the parking lot are paint’s natural enemies. In 2014 Nissan tested a Note with a special paint job in cooperation with the specialist firm Ultratech. Nanoparticles in the paint create a kind of air barrier on the surface, repelling mud, raindrops and other dirt. However, the company is not pursuing series application of this paint. So carwashes are not going to disappear any time soon. But if their brushes or cloths are soiled, they act like sandpaper and damage the paint surface, causing scratches. Researchers at the Harbin Institute of Technology in China recently developed a soft, dynamic coating intended to function like human skin. It is made from a thermoplastic synthetic and tannic acid. When combined with the nanomaterial graphene oxide, a certain minimum thickness of the composite demonstrates self-healing properties. But industrial application is still a long way off.

Researchers at Saarland University have gone further and presented a different solution: polyrotaxanes, whose molecules are arranged like strings of pearls. This structure enables them to re-seal cracks and scratches in smooth and glossy surfaces, because the individual molecules flow and mingle with others. And Nissan has already patented its “Scratch Shield” for self-healing paints. An elastic resin is added to the clearcoat, which when heated eliminates small scratches all by itself. The “healing process” takes between one hour and one week. And until now, there was also no paint that could avoid smeary finger marks and handprints. The Fraunhofer Institute for Microstructure of Materials and Systems is now developing a nano paint with an anti-fingerprint surface that has self-cleaning properties.

Color, change thyself!

The graffiti artist René Turrek has developed a special paint for cars, which he applies solely with spray cans and marker pens. When the paint comes into contact with water, it will change color completely, or show figures and patterns. The trick also works when the temperature changes. But supposing you could change your car’s paint job by voice control? You want a serious silver today for a meeting, and tomorrow a bright red for a weekend away? Or how about a vehicle that changes color after an accident in order to attract attention? Nanotechnology could soon make that a reality. One approach being considered is to add micro particles to the paint, which could change their color when subjected to electrical impulses. But what happens when you’re on the road at nighttime? Pioneering Nissan has developed a kind of paint that absorbs the sun’s UV light by day so that the vehicle will fluoresce for up to ten hours at night. And it does so without using electricity. The Japanese manufacturer’s project benefits from the British engineering firm Pro-Teq Surfacing that develops footpaths that glow in the dark.

And why not also use paint to generate electricity that is fed into the network through a vehicle-to-grid system? Maybe in a few years from now, solar modules will look more like thin films or paints than today’s conventional metal-framed solar cells made of silicon. Billions of cars would mutate into power plants and revolutionize the energy supply of tomorrow. So paint is going to be a multitasker par excellence. In just a few years, we will be able to choose between paints with various functions – combined with all conceivable colors for a daily choice. This means that visitors attending future IAAs will no longer discuss only a paint’s color and the impression it makes, but also its functions and capabilities.

Stagephoto: © BMW Group

The slogan of the IAA 2019 is “Driving Tomorrow.” The focus is once again on exterior trends. So it will be exciting to see what innovations concerning paint will appear this year. Order your ticket and discover the mobility of tomorrow.