Adjusted Functional Surfaces by Nanotechnology for Automotive Applications
Group Research, Materials, Volkswagen AG,
Wolfsburg D-38436 GERMANY
This is an abstract
for a presentation given at the
Foresight Conference on Molecular Nanotechnology.
There will be a link from here to the full article when it is
available on the web.
Customer demands for conveniences and safety of automobiles are still increasing. It is for example not acceptable that windscreens and transparent covers of headlights steam up inside at certain weather conditions. On the other hand there is always the desire for clean surfaces inside and outside the car. The interaction between any technical surface and omnipresent water depends on the surface free energy. Moreover the surface free energy can be influenced by certain chemical groups sticked to the surface using chemical nanotechnology. In the present paper coatings with different surface free energies are discussed for automotive applications. Hydrophilic surfaces, i.e. high surface free energy, are achievable by using either different surfactants in different resins or a mixture of titania and silica. With such coatings it can be avoided, that surfaces steam up. However, the durability of hydrophilic coatings is not yet ensured. Possible automotive applications are all surfaces, where the mechanical load is small, e.g. the inside of glazing or covers of headlights. Hydrophobic surfaces, i.e. low surface free energy, has been realised either by adding fluorinated hydrocarbons in a silica backbone or by an adjusted roughness of the surface. On hydrophobic surfaces the soiling is strongly reduced, if enough water is present. A significant disadvantage of nano- or microstructured hydrophobic surfaces for automotive applications like rims or outside rear-view mirrors is still the low mechanical resistance. Depending on weather conditions and driving situations, it is desired to have either a hydrophilic or a hydrophobic behaviour of the surface, which leads to the need for switchable coatings. This will be a topic of future research.
Group Research, Materials, Volkswagen AG
Letter Box 1511, Wolfsburg D-38436 GERMANY