Both Water and Oil Roll off New Material
KARLSRUHE, Germany - Both water and oil droplets roll off a new class of highly fluorinated super-repellent polymers called “fluoropore.” Germany’s Federal Ministry of Education and Research (BMBF) has allocated €2.85 million for further development of the material by researchers at the Karlsruhe Institute of Technology (KIT). Fundamental research in this area is aimed at making use of this new material for universal protective coatings.
The phenomenon of water droplets rolling off of leaves is found in lotus plants as well as cabbage. For some time, this lotus effect has been used to produce rough surfaces with special chemical properties. “However, this trick does not work for oils – the lotus plant repels water, but no oil,” said Bastian Rapp of the KIT Institute of Microstructure Technology (IMT). “Oil-repellent surfaces need to have another chemical structure, fluoropolymers are required for this purpose.” Fluoropolymers are high-performance plastics with a high heat resistance and chemical stability. Teflon, the known anti-stick coating material for frying pans, belongs to this category of substances.
“When combining the chemical properties of fluoropolymers with the roughness of the lotus plant, surfaces are obtained from which both water and oil droplets will roll off,” Rapp explained. He has already succeeded in producing such super-repellent surfaces with this effect in the laboratory. In practical use, however, they turned out to have an insufficient stability. A big problem is sensitivity to abrasion. Rapp is working on developing a new class of fluorinated polymers that repel water and oil and are far more robust in practical applications. These polymers, called fluoropore, will provide these characteristics on nearly any surface.
The research project of the young KIT scientist was recently recognized at the NanoMatFutur competition for young scientists launched by the Federal Ministry of Education and Research (BMBF). Rapp’s project “Fluoropore – chemically inert, micro- to nanoporous ‘teflon’ with an adjustable wetting behavior” was granted €2.85 million for the establishment of a young investigator group for the next four years.
With fluoropore, coatings with universal protection against any type of staining can be produced. An example is a coating for car windows that would prevent water from condensing and freezing in winter. Other examples are fine-pore screens, whose chemistry and structure allow for the separation of oil and water mixtures used as cooling lubricants in the processing industry.