Empa develops water-repellent textiles without PFAS

In future, raincoats, swimming trunks, or upholstery fabric may be manufactured with water-repellent textiles that have not been treated with chemicals that are harmful to health and the environment. This is because Empa and the textile companies Lothos KLG, Bäumlin & Ernst, and AG Cilander have developed a water-repellent coating without using harmful per- and polyfluoroalkyl substances (PFAS).

These have been used in manufacturing, for instance for functional clothing and skillets, since the 1970s. PFAS do not readily biodegrade so they build up in the environment and eventually in the human body. They are suspected of causing cancer, excess weight, and cardiovascular diseases.

Dirk Hegemann from the Empa Advanced Fibers laboratory in St.Gallen explaines in a press release that instead of PFAS, the team used “highly cross-linked siloxanes, which create silicone-like layers and – unlike fluorine-containing PFAS – are harmless.” The textile fibers receive a coating of atomized siloxanes that is 30 nanometers thin. This project was supported by Innosuisse.

Hegemann added: “We have even succeeded in permanently impregnating more demanding, elastic fibers with the new process, which was previously not possible.” According to the information provided, tests have shown that they even soak up less water and dry more quickly with the environmentally friendly coating versus fabrics coated in PFAS. Furthermore, while PFAS coatings on stretchy textiles decrease after several washes, the fluorine-free coating remains at a high level.

The new procedure is currently being scaled for efficient, economically viable industrial processes. According to Hegemann, there has been great interest in this alternative from industry. ce/mm