Nanocoated prevents greasy application

A new nanocoating developed by Fraunhofer researchers could in the future prevent annoying stains from fingers touching stainless steel surfaces.
shiny new fridge features a glamorous stainless steel front. However, soon after, the door was covered with black fingerprints, which were difficult to remove with cloth and detergent; This work actually requires some hard polishing

. Fingerprints like this are not just ugly, grease films can also attack metal surfaces.
farewell to the greasy smears
and their colleagues at FEW Chemicals GmbH in Wolfensohn, researchers from the Fraunhofer Institute for Materials and Systems Microstructures in Harley are working to stop them. The secret is a coating with special additives that are waterproof and oil-resistant. The effect of this layer is two-p.m.: when particles from the coating are deposited on a stainless steel surface, the surface becomes coarser and its surface area increases. When the finger comes into contact with the refrigerator door, it touches only the convex starting point on the surface, and the grease on the fingertips never reaches the "valley" of the stainless steel surface. This means that the surface area is actually in contact with the stainless steel surface. Grease remains small. In addition, the refractive index of the coating is adjusted to match the skin's natural oil content. This means that the stainless steel surface on which the light is coated is reflected in much the same way as the surface touched by the sticky finger. As a result, fingerprints are almost imperceptible.
layered systems
while FEW Chemicals GmbH is working on coating systems, the Fraunhofer team is focusing on the analysis of these layers. "We are looking at layers created not only using optical microscopes, but also scanning electron microscopes and atomic force microscopes. We look at the size of individual particles in the coating system and whether they are evenly distributed. The additives used are another focus of our analysis," said Dr Jessica Klehm, research assistant at Bio and Polymer Materials, fraunhofer IMWS. These issues are important in assessing the quality of the coating. For example, if nanoparticles gather to form larger particles, the coating may lose its transparency as a result.
some challenges must be overcome before these investigations can be conducted. First, the sample must be recycled in size. The best study of optical microscope and further study of other methods requires that the thickness of the sample should not exceed 60 to 80 microns, i.e. about the thickness of human hair; Checking under a transmission electron microscope even requires a sample to be a thousand times thinner. "We can't cut samples with saws, which can damage the coating. So we embed the sample in the resin and grind it to the desired thickness," explains Dr Klehm.
to quantify the anti-fingerprint effect of
, in addition, researchers are developing an automated test machine for each layer. The device is not used to study particles in the coating, but for the visibility of the fingerprint itself. The machine impregnates the seal in a solution that is similar in composition to an oily film on human skin. This seal automatically works and lasts the same force and duration, then pressed on the coating surface, leaving a "fingerprint". The machine will use a combination of spectroscopic and optical procedures to analyze how much solution is left on the surface and, therefore, to achieve a percentage value that represents the coating's anti-fingerprint effect. Scientists are trying to find the ideal combination of analytical devices.
researchers have found favorites in the various coating systems they surveyed. The task now is to further optimize the system. Development activities should be completed by the end of 2020, when industrial-scale production of coating systems will be handed over to FEW Chemicals GmbH.