2 days ago
Scientists create ultra-repellent non-stick coating for safer cooking at home
Teflon and other PFAS (per- and polyfluoroalkyl substances) have long been prized for making cookware, packaging, and fabrics resistant to water and grease. But these 'forever chemicals' don't break down in nature and tend to accumulate in the human body, posing serious health and environmental risks.
Now, researchers at the University of Toronto have created a promising alternative that delivers high performance with much lower risk.
Their new coating repels water and oil as effectively as standard non-stick materials, but contains only trace amounts of the least harmful PFAS variant.
Silicone base with PFAS twist
The team used polydimethylsiloxane (PDMS), commonly known as silicone, as the base for their new material.
'PDMS is often sold under the name silicone, and depending on how it's formulated, it can be very biocompatible — in fact it's often used in devices that are meant to be implanted into the body,' said Professor Kevin Golovin, who leads the Durable Repellent Engineered Advanced Materials (DREAM) Lab.
However, PDMS on its own falls short of matching PFAS when it comes to repelling oil and grease.
The breakthrough came when PhD student Samuel Au developed a method to enhance the material's performance through what the team calls nanoscale fletching.
Nanoscale fletching for repellency
'Unlike typical silicone, we bond short chains of PDMS to a base material — you can think of them like bristles on a brush,' Au explained.
To improve their oil-repelling power, the team added the shortest possible PFAS molecule, consisting of a single carbon atom bonded to three fluorine atoms, to the tips of those bristles.
'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. That's called fletching, so this is nanoscale fletching.'
When the researchers tested the coated fabric with oil droplets, the material achieved a grade of 6 on a standard repellency scale used by the American Association of Textile Chemists and Colorists.
That's on par with many commercial PFAS-based coatings.
Low risk, commercial potential
'While we did use a PFAS molecule in this process, it is the shortest possible one and therefore does not bioaccumulate,' said Golovin. '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.'
'Our hybrid material provides the same performance as what had been achieved with long-chain PFAS, but with greatly reduced risk.'
The team hopes to collaborate with manufacturers to scale up the process and bring the product to market. Meanwhile, research continues.
'The holy grail of this field would be a substance that outperforms Teflon, but with no PFAS at all,' Golovin said. 'We're not quite there yet, but this is an important step in the right direction.'
The study is published in the journal Nature Communications.
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