PTFE
A fluoropolymer used in some non-stick pan coatings.
- Also known as
- polytetrafluoroethylene, polytetrafluoroethene
In everyday products
- Non-stick frying pan — Non-stick coating
Structure and behaviour
[–CF₂–CF₂–]ₙ
The tetrafluoroethene double bond becomes a carbon backbone bearing fluorine atoms. PTFE is an addition polymer; its fluorinated surface gives very different interactions from hydrocarbon polymers such as PE.
- Low surface energy reduces wetting and adhesion, explaining release behaviour at a coating surface.
- Low friction is a surface property; it does not make a thin coating responsible for a pan’s mechanical strength.
- The pan’s metal supplies most structural support and heat conduction, while the polymer-containing surface provides release.
- Coating manufacture uses formulated dispersions; other PTFE grades are processed as powders or by paste extrusion.
- A difficult-to-wet surface also makes adhesion to the substrate a design problem, addressed by surface preparation and coating layers.
Preparation routes
Tetrafluoroethene route
Addition polymerisation. Tetrafluoroethene builds the PTFE chain. An emulsion-polymerisation route supplies fine PTFE particles in an aqueous dispersion for formulated coatings. Addition consumes the C=C bond while retaining fluorine substituents. Coating release behaviour arises from the polymer surface, not from unreacted tetrafluoroethene.
Industrial initiators and dispersion controls support polymerisation. Coating makers combine the polymer with other ingredients; applying a coating is a separate manufacturing step. The traced dispersion is one product form; PTFE powder processing and cookware coating are distinct operations.
Material limits
PTFE coating systems include primers, binders and fillers. Coating recovery and metal-pan recycling use separate processes.