From frying pans to raincoats, oil-repelling surfaces are everywhere. But the chemicals that make them slick, known as PFAS (per- and polyfluoroalkyl substances), have come under fire for their environmental and health risks. Now, a team of researchers at the University of Toronto Engineering may have found a cleaner way forward.
Their newly developed material repels both water and grease just as effectively as traditional non-stick coatings, but with far less PFAS involved. That’s a big deal, considering PFAS are often called “forever chemicals” for their tendency to linger in the environment and accumulate in living organisms.
Oil repellency isn’t just about keeping your shirt stain-free. It’s key to self-cleaning surfaces, anti-soiling fabrics, and protective coatings in industries like textiles, healthcare, and electronics. PFAS have long been the go-to for these jobs, especially the long-chain versions, which are now banned or restricted due to links with cancer, congenital disabilities, and other health issues.
Short-chain PFAS are considered less harmful, but even they are under scrutiny. The problem? Few alternatives match their oil-repelling power.
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The Toronto team turned to polydimethylsiloxane (PDMS), a silicone-based material known for its biocompatibility. It’s often used in medical implants, but until now, it couldn’t match PFAS in repelling oil.
To change that, PhD student Samuel Au developed a clever new technique called nanoscale fletching. Think of it like crafting a microscopic brush: short PDMS chains are bonded to a surface like bristles. Then, each bristle tip gets a tiny PFAS molecule, just one carbon and three fluorines.
Zoom in to the nanometre scale, and the structure resembles the feathers at the back of an arrow, which inspired the name “fletching.”
To test their creation, the team coated fabric with the new material and dropped various oils on it. The result? A grade of 6 on the American Association of Textile Chemists and Colorists scale: matching many standard PFAS coatings.
And because the PFAS used is so short, it doesn’t bioaccumulate like its longer cousins. That means similar performance with significantly lower risk.
The researchers believe this hybrid material could be a game-changer for industries looking to ditch harmful chemicals without sacrificing performance. They’re open to working with manufacturers to scale up the process and are already exploring even safer alternatives.
Their ultimate goal? A material that outperforms Teflon, without any PFAS at all. While that dream isn’t a reality yet, this breakthrough brings it much closer.
In the world of non-stick science, tiny bristles and smart chemistry might be the key to a cleaner, safer future.
Journal Reference:
- Au, S., Gauthier, J.R., Kumral, B. et al. Nanoscale fletching of liquid-like polydimethylsiloxane with single perfluorocarbons enables sustainable oil-repellency. Nat Commun 16, 6789 (2025). DOI: 10.1038/s41467-025-62119-9