Researchers develop safer alternative to PFAS in non-stick coatings

A breakthrough in the search for safer substitutes for per- and polyfluoroalkyl substances (PFAS)—commonly known as "forever chemicals"—has emerged from the Sustainable Repellent Engineered Advanced Materials (DREAM) Laboratory at the University of Toronto. Their recent publication in Nature Communications introduces a new silicone-based material that exhibits competitive performance with traditional PFAS while significantly reducing environmental and health risks.  

PFAS have long been valued for their unique properties, particularly their remarkable ability to repel water and grease. This is due to the strong bond formed between carbon and fluorine atoms, which makes these substances not only effective but also resistant to degradation. As a result, PFAS linger in the environment and accumulate in biological tissues, raising alarms over their links to serious health issues, including cancer and developmental problems.  

Currently, alternatives to PFAS have struggled to match their performance, especially in applications requiring both water and oil repellency. The new material developed by the researchers leverages polydimethylsiloxane (PDMS), a silicone known for its biocompatibility and use in medical devices. The researchers aimed to enhance PDMS's repellency through a novel technique they call "nanoscale fletching," inspired by the aerodynamic design of arrows.  

In this innovative approach, the researchers bonded short chains of PDMS with the shortest possible PFAS molecule, consisting of just one carbon atom and three fluorine atoms (CF3). Each PDMS molecule can attach up to seven of these small PFAS units, creating a structure reminiscent of the fletching on an arrow, which optimally positions the coating for maximum efficacy.  

Testing their hybrid material, the researchers coated fabric samples and subjected them to various oily substances. Using an evaluation scale from the American Association of Textile Chemists and Colorists, they achieved an impressive average score of six—on par with many conventional PFAS coatings. This performance demonstrates that the new material can effectively rival the capabilities of traditional options like Teflon, but with a significantly lower environmental footprint.  

While the new silicon-based coating is not entirely free of PFAS, the use of the shortest PFAS molecules minimizes the risk of bioaccumulation, addressing a critical concern linked to longer-chain variants. The hazardousness of PFAS compounds increases with chain length; therefore, this approach allows to leverage the benefits of PFAS with much-reduced risks.  

With growing regulatory scrutiny and calls for bans on harmful PFAS, the timing of this research couldn't be better. The team is eager to collaborate with manufacturers interested in scaling up the production of this new coating, which could be particularly beneficial for food-contact materials and various consumer products.  

While the researchers have not yet reached the holy grail of creating a substance that completely outperforms Teflon without any PFAS, this advancement marks a significant step forward in the quest for safer materials. As the research progresses, the hope remains that a completely PFAS-free alternative will soon be within reach.  

Source:  

Nature