Polychlorotrifluoroethylene

Polychlorotrifluoroethene (PCTFE or PTFCE) is a thermoplastic chlorofluoropolymer with the molecular formula (CF₂CClF)_n, where n is the number of monomer units in the polymer molecule. It is similar to polytetrafluoroethene (PTFE), except that it is a homopolymer of the monomer chlorotrifluoroethylene (CTFE) instead of tetrafluoroethene. It has the lowest water vapor transmission rate of any plastic.