Teflon replacement up to scratch, but at a price

A tougher, more hard-wearing polymer, developed by NASA, could eventually sound the death knell for Teflon, according to a University of North Texas researcher. Witold Brostow had been seeking a material with greater durability and scratch resistance than Teflon and other PTFE coatings, when colleagues at Texas State University suggested he try an additive they had developed for NASA.

The addition of the compound into a polymer resulted in a material with similar non-stick characteristics to Teflon, but with much improved hardness, Brostow found.

‘The material is a polymer (12FPEK) containing fluorine, which contributes the critical, including non-stick, properties,’ explained Patrick Cassidy, at Texas State University. NASA and the university have patented the polymer as a low dielectric film, with good electrical insulating properties. It is also colourless, soluble, easy-to-process and thermally stable, withstanding temperatures of up to 540˚C. ‘This combination of properties is quite rare,’ according to Cassidy.

Materials created with this additive had comparable friction to Teflon while offering greater scratch resistance or toughness due partly to the crosslinking of the polymer chains in the presence of the additive. However, at $100/g, the cost was prohibitive, said Brostow. ‘What we are working on now are materials with similar properties, and not very different chemical structures, but which are affordable.’

The cost of the NASA additive was due to fluorine, a difficult and expensive material to work with, Cassidy noted. It was originally developed for resistance to low earth orbit as a coating for space station parts, but has since been used in electronics and by the cosmetic industry in fingernail polish due to its glossy appearance and thermal stability.

Brostow continues to work on a replacement additive and believes his group can create a material to outperform Teflon in wear and tear within a few years. ‘It’s likely we’ll have something in the next three years, which would be ten years from when we started,’ he said. ‘If we could have a larger team of people working on this project, we could get results faster. But the attitude of industry is to wait and see.’