Polytetrafluoroethylene (PTFE) is a fully fluorinated polymer. It has a smooth surface and, as a result, has a low friction coefficient. PTFE is physiologically inert, chemically resistant and impervious to diffusion. Pure PTFE is only suitable for use with abrasion to a limited extent since cold flow quickly arises.

The biggest advantage of PTFE is that it is resistant to almost all chemicals. However, PTFE is not resistant to liquid alkaline metals, gaseous fluorine and certain fluoride chemicals such as chlorine monofluoride or oxygen fluoride. In addition, PTFE is only useable with abrasive materials to a limited extent.