Not only are greasy fingerprints on shiny stainless steel surfaces unattractive, they also attack the surface. A new nanocoating being developed by Fraunhofer researchers will in the future prevent the annoying smudges that result from fingers touching stainless steel surfaces. The key to their approach: special nanoparticles added to the coating.
The shiny new refrigerator features an attractive stainless steel front. But it doesn’t take long before the door is covered in dark fingerprints that are difficult to remove with only a cloth and detergent; the job actually calls for some arduous polishing. Fingerprints like these are more than just unsightly, the grease film also attacks the metal surface.
Say goodbye to greasy smears
Together with their colleagues at FEW Chemicals GmbH in Wolfen, researchers from the Fraunhofer Institute for Microstructure of Materials and Systems IMWS in Halle are now working to put an end to smears like these. The secret lies in a coating layer containing special additives and which is water and oil repellent. This layer’s effects are twofold: When the particles integrated in the coating settle on the surface of the stainless steel, the surface becomes rougher and its surface area increases. When a finger comes into contact with the refrigerator door, it only touches the raised points on the surface and the grease on the fingertip never reaches the “valleys” of the stainless steel surface. This means the surface area which actually comes into contact with the grease is kept very small. In addition the refractive index of the coating has been adjusted so that it matches that of the skin’s natural oil content. This means light is reflected by the coated stainless steel surface in about the same manner as by a surface that has been touched by sticky fingers. As a result, the fingerprints are hardly noticeable.