Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene, most famously used as Teflon® by DuPont as a non-stick coating for pans and cookware. It can be used for printed circuit boards, bearings, gears, and thread seal tape in plumbing.

PTFE was discovered by accident in 1938 by Roy Plunkett. Plunkett was working on an experiment for Kinetic Chemicals to create a new refrigerant. He used tetrafluoroethylene gas in a bottle and found that extra weight had been added to the bottle unexpectedly. He sawed open the bottle and found it coated with a waxy white substance. The tetrafluoroethylene had polymerized into perfluoroethylene due to the iron at high pressure. Kinetic Chemicals, which was founded by DuPont and General Motors patented it in 1941, and in 1945, trademarked the brand Teflon®.