Chapter 10: Chlorotrifluoroethylene Copolymers for Energy-applied Materials Check Access

In the series of fluorinated monomers, chlorotrifluoroethylene, F₂CCFCl (CTFE), is the most often used fluoroalkene after tetrafluoroethylene (TFE) and vinylidene fluoride. Similarly to those two, it can be (co)polymerized under radical initiation. TFE and CTFE behave similarly in homopolymerization and in copolymerization because they are electron-poor monomers (e>1.5). However, several differences were observed, such as better thermal stability of TFE copolymers but better processing and performance of CTFE copolymers (PCTFEs) for coatings since PCTFE is the most efficient gas barrier polymer. CTFE has been extensively studied in radical copolymerization to obtain alternating copolymers in the presence of ethylene, propylene or electron-donating monomers such as vinyl ethers, or with other monomers to yield statistical copolymers. The use of PCTFEs for energy related-applications such as fuel cell membranes (proton, alkaline and quasi-anhydrous), polymer electrolytes for lithium ion batteries or items for electronics and electroactive or relaxor ferroelectric devices is reviewed. More recently, a straightforward strategy concerning the synthesis of original functional alternating copolymers by the radical alternating copolymerization of CTFE with 2-chloroethyl vinyl ether led to a wide range of copolymers in which the functional group [phosphonic acid, ammonium, benzimidazole or triazole or oligo(ethylene oxide)] brings complementary properties for uses such as proton-conducting or alkaline exchange membranes, binders or electrolytes for proton exchange membrane fuel cells, lithium ion batteries and materials for photovoltaic devices.