Researchers have reimagined the slippery surface that changed kitchens and industries alike. In a new study, engineers from the University of Toronto (U of T) unveiled a nonstick coating that repels oil and water as effectively as Teflon—without relying on the toxic class of chemicals that made Teflon infamous.
This innovation, detailed in Nature Communications, could reshape how we think about slick surfaces, from frying pans to fabrics, with profound implications for human health and the environment.
Rethinking the Chemistry of Repellency
For decades, the gold standard of nonstick performance has come from PFAS—per- and polyfluoroalkyl substances. These synthetic molecules have been used in everything from raincoats to medical tubing. Their secret lies in chains of carbon and fluorine atoms, which resist sticking to nearly anything, even grease. But there’s a catch.
Long-chain PFAS like PFOA (used in older Teflon products) have been linked to cancer, birth defects, and other health issues. They’re also “forever chemicals” meaning they don’t really degrade and stay around for a long time. While shorter-chain PFAS are considered somewhat safer, they still linger in the environment and the search for alternatives has so far come up short.
The breakthrough came by turning to polydimethylsiloxane, or PDMS—a silicone polymer already used in everything from contact lenses to biomedical implants. It’s flexible, biocompatible, and heat-resistant. But on its own, PDMS struggles to repel oil.
To address that, lead author Samuel Au and colleagues invented a method they call nanoscale fletching—named after the feathery tail on an arrow that stabilizes its flight. In their chemical version, they “fletched” the ends of PDMS molecular chains with tiny, slippery groups made of one carbon atom bonded to three fluorines (-CF₃).
“If you were able to shrink down to the nanometre scale, it would look a bit like the feathers that you see around the back end of an arrow, where it notches to the bow,” said Au. “That’s called fletching, so this is nanoscale fletching.”
These bristled, liquid-like structures allow the -CF₃ groups to migrate to the outermost surface, creating a skin that mimics the repellency of Teflon.
And remarkably, it works. The coated materials scored a “6” on an American Association of Textile Chemists and Colorists (AATCC) oil repellency scale. That grade is on par with existing PFAS-based coatings. But with a fraction of the fluorine content.
A Tiny Molecule With Big Impact
The -CF₃ group isn’t just small—it’s the shortest possible PFAS molecule. That matters a lot.
“What we’ve seen in the literature, and even in the regulations, is that it’s the longest-chain PFAS that are getting banned first, with the shorter ones considered much less harmful,” said said Kevin Golovin, the study’s senior author and head of the Durable Repellent Engineered Advanced Materials (DREAM) Lab at U of T Engineering.
Studies suggest that -CF₃ doesn’t accumulate in the body like its longer cousins. Scientists believe the coating primarily breaks down into trifluoroacetic acid, which the body excretes easily and which poses far lower toxicity to humans and aquatic life.
Even when sprayed continuously with oil, the PDMS coatings shed droplets like a duck’s back. They managed to maintain their dry surface far better than traditional silicone coatings.
Beyond lab tests, the team coated nylon, polyester, aluminum, and stainless steel with the new material. It performed well across the board—even on textured or porous surfaces like fabric and wire mesh, which often defeat traditional nonstick coatings.
They also tested the coating’s limits: heating it to 200°C, blasting it with water jets, and soaking it in acidic and basic solutions. It held up.
“The holy grail of this field would be a substance that outperforms Teflon, but with no PFAS at all,” said Golovin. “We’re not quite there yet, but this is an important step in the right direction.”
What About Long-Term Safety?
Despite promising results, some scientists caution that even short-chain PFAS, including -CF₃, are not entirely benign. Trifluoroacetic acid, the likely breakdown product of the coating, is persistent in the environment and has sparked debate about its long-term impact.
The authors argue that the quantities involved are minuscule. The total potential emissions from a single jacket coated with their material, they estimate, would equal just over an hour’s worth of refrigerant leakage from a car’s air conditioner.
And yet, as governments around the world move to regulate PFAS as a class—including proposals in the EU to ban thousands of compounds—these ultrashort-chain options may be a transitional solution, not a final one.
What this study ultimately shows is that it may not take a long chain of fluorinated atoms to create a high-performance nonstick surface. A few strategically placed molecules might do the trick—with far fewer risks.
“This disproves the decades-old belief that the liquid repellency of PFAS is inherently coupled with chain length,” the researchers write in their paper.
The journey away from forever chemicals is likely to be long. But in the flicker of a droplet sliding off a nanoscale brush, we may be seeing the future take shape.
