In chemistry, Polytetrafluoroethylene (often shortened to PTFE) is a polymer of tetrafluoroethylene. It is a fluoropolymer, because the polymerization is based on strong bonds of fluorine and carbon. Polytetrafluoroethylene is not very reactive. It also repels oil and water. E. I. du Pont de Nemours and Company developed it in 1938. It is better known by its trade-names, "Teflon", and Gore-Tex. Teflon is a coating done to frying pans, among others. Gore-Tex is a membrane used in clothing.