What makes a non-stick pan non-stick?

A non-stick pan is coated with PTFE, a plastic that almost nothing wants to cling to. PTFE, or polytetrafluoroethylene, is a synthetic fluoropolymer: a long chain made wholly of carbon and fluorine. It is heat resistant and chemically inert, and it is hydrophobic, so neither water nor water-containing substances wet it. Fluorocarbons show only small London dispersion forces, because fluorine is not easily polarized by electric charges. The result is one of the lowest coefficients of friction of any solid. It resists van der Waals forces so well that it is the only known surface to which a gecko cannot stick.

The discovery was an accident. On 6 April 1938, Roy Plunkett and his assistant at DuPont were trying to make a new refrigerant when they found that a cylinder of tetrafluoroethylene gas contained a white powder: PTFE. They sawed the bottle open and found its inside coated with a waxy white material that was oddly slippery.

The pan came later, and thanks to a home cook. In 1954, Colette Grégoire urged her husband Marc, a French engineer, to try on her cooking pans the material he had been using on fishing tackle. He went on to create the first PTFE-coated non-stick pans under the brand name Tefal.

Today PTFE is entangled in a debate. PTFE and chemicals used in making it are among the best-known PFAS, a family often called forever chemicals because of their long environmental lifetimes. DuPont used one of them, PFOA, for decades before discontinuing it after legal actions. Non-stick cookware itself was not found to be a major source of PFOA exposure, but the wider question about PFAS is still being assessed.