Dirk Hegemann from Empa's Advanced Fiber Laboratory in St. “We use so-called highly cross-linked siloxanes, which create silicone-like layers and—unlike fluorinated PFAS—are harmless,” Gallen explains in a release from Empa. Siloxanes are organic compounds containing a functional group consisting of two silicon atoms bonded to an oxygen atom.
To coat textile fibers, siloxane is atomized and activated in a reaction gas. As a result, they retain their functional properties and encase the textile fibers in a water-repellent coating as thin as 30 nanometers (nm).
The Swiss Federal Materials Research and Testing Laboratory has developed an environmentally friendly process to create fibers with a water-repellent finish. For coatings, highly cross-linked siloxanes are atomized and activated in the reaction gas. They retain functional properties and encase the fibers in a 30 nm thin water-repellent coating.
Fibers coated in this way can then be processed into waterproof textiles for use in clothing and upholstery.
The project is being funded by Swiss innovation agency Innosuisse.
The new process has many advantages over the conventional wet chemical process. Even with textiles with complex structures, seamless distribution of hydrophobic substances into all loops of the interwoven fibers is ensured.
This is important because even a small wet spot is enough for water to penetrate deeply into the swim trunks, preventing the clothes from drying quickly.
“We even succeeded in permanently impregnating the more demanding, elastic fibers with the new process, which was not possible before,” says Hegemann.
In initial laboratory analyses, textiles made from the new fibers performed slightly better than conventional PFAS-coated fabrics. They absorb less water and dry faster.
However, the magical properties of fluorine-free coatings only really kick in after the textile has been washed several times: While the performance of conventional PFAS coatings on stretch textiles is significantly reduced After repeated washing cycles, fluorine-free fibers retain their magical properties. waterproof properties, the release said.
Hegemann and his team are now working to scale this process into efficient and economically viable industrial processes.
PFAS, per- and polyfluorinated alkyl compounds, are a group of synthetic chemicals that have many applications due to their ability to repel water, oils and greases.
They have been used since the 1970s, for example in the production of functional clothing, fire extinguishers and frying pans.
Because carbon-fluorine substances do not decompose but accumulate in the environment and ultimately in the human body, they are called 'forever chemicals'.
These substances are suspected of causing various health problems in humans and animals, such as cancer, cardiovascular disease, obesity, and developmental disorders. Certain PFAS have been banned.
Fiber2 Fashion News Desk (DS)
