Transparent Coating for Everyday Applications

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This water-repellent ability is known from nature, especially in lotus plants where water droplets simply roll off the leaf's surface. Researchers imitate this lotus effect with superhydrophobic surfaces. At Karlsruhe Institute of Technology's (KIT) Institute of Microstructure Technology (IMT), Dr. Bastian E. Rapp's team is developing a new class of such materials called Fluoropor. The researchers have combined the properties of fluoropolymers with the roughness known from lotus leaves, thereby obtaining surfaces that are both oil- and water-repellent. The new materials are characterised by a high chemical and thermal stability according to KIT. Together with scientists from KIT's Institute for Applied Materials Computational Materials Science (IAM-CMS), Dr. Rapp's researchers have for the first time succeeded in developing a fluorinated polymer foam that is both transparent and insensitive to abrasion. This material is presented in Nature's Scientific Reports journal. 

Superhydrophobic properties develop due to structuring on the nano/scale and microscale. Such extremely fine structures make surfaces fundamentally highly sensitive to abrasion, and hence insufficiently robust for everyday applications. In contrast, Fluoropor's nano/microstructure is not limited to the surface but extends throughout the bulk of the material, lending the material a high degree of abrasion resistance and rendering it suitable for daily use in the long term. Due to Fluoropor’s foam-like structure with pore sizes below the wavelength of visible light, it appears optically transparent, making it ideally suited as a coating for glass. The material, can, however, also be applied to other materials such as metal, polymers, or textiles. Fluoropor can be cost-effectively manufactured to different thicknesses by a one-stage photo-induced radical polymerisation process. The German Federal Ministry of Education and Research is funding this work as part of the NanoMatFutur programme.