I’ve warned my family that if I ever go missing, it’s probably because I was committed after obsessively trying to wipe fingerprints and grease stains off of our stainless steel kitchen appliances. Anyone who’s made the upgrade to the brushed metal finish knows this pain all too well, but German chemists may have finally come up with a solution with a simple coating that makes those blemishes almost invisible to the naked eye.
Every time you touch something you leave behind a thin layer of grease from your fingertips. It’s rarely noticeable (unless you’re a crime scene investigator) except on smooth and shiny surfaces like mirrors or highly reflective steel panels, like those found on many modern appliances. Brushed metal poses additional challenges as the surface features shallow grooves where grease can get easily trapped. So not only are smears and fingerprints more obvious, they’re much harder to wipe away.
To help remedy what is possibly the most annoying part of your shiny new kitchen upgrade, researchers and chemists from the Fraunhofer Institute for Microstructure of Materials and Systems IMWS worked with experts from FEW Chemicals GmbH in Wolfen, Germany, to develop a new coating with added particles that help make it both water and oil repellent. When applied to a brushed stainless steel surface, those particles in the coating settle and create deeper ridges and an overall rougher finish. Fingers still leave grease behind when touching it, but it only ends up on the raised parts of those ridges which has a much smaller surface area than the rest of the stainless steel. The grease isn’t able to penetrate into the deeper valleys, which also makes it much easier to simply wipe away.
That’s not the coating’s only trick to making fingerprints vanish, though. The chemists who developed it also found a way to adjust the coating’s refractive index—how much a path of light is bent when passing through a material—to match the refractive index of the skin’s natural oils that make up a fingerprint. It affects light very differently to how stainless steel does, which is what makes fingerprints and grease stains stand out. But with the two matched after the coating is applied, fingerprints and grease marks become far less noticeable.
The effectiveness of the new coating is being tested and optimised by the Fraunhofer Institute, but it expects a final recipe for the coating to be perfected by the end of 2020, at which point FEW Chemicals GmbH will put it into mass production and make it available to appliance makers. Whether or not the coating needs to be applied during the manufacturing process, or if it can be applied to existing appliances, remains to be seen. So if you’re the type who can’t just ignore fingerprints, you might want to put off a kitchen renovation for at least another year.
Featured image: Fraunhofer IMWS