Proton-conducting polymer electrolyte membranes based on fluoropolymers incorporating perfluorovinyl ether sulfonic acids and fluoroalkenes: Synthesis and characterization

Abstract

This paper presents the synthesis of new polymer electrolyte membranes based on fluoropolymers incorporating aromatic perfluorovinyl ether sulfonic acids. A novel synthetic route describing the preparation of perfluorovinyl ether monomer containing sulfonic functionalities, 4-[(α,β,β- trifluorovinyl)-oxy]benzene sulfonic acid (TFVOBSA), is reported. The radical (co) and terpolymerisation of 4-[(α,β,β-trifluorovinyl) oxylbenzene sulfonyl chloride (TFVOBSC) with 1,1-difluoroethylene (or vinylidene fluoride, VDF), hexafluoropropene (HFP), and perfluoromethyl vinyl ether (PMVE) is described. The terpolymers of TFVOBSC with VDF and HFP, or VDF and PMVE, were hydrolysed and also led to new fluorinated terpolymers bearing sulfonic acid aromatic side-groups. The terpolymers were characterized by 1H and 19F NMR spectroscopies, SEC, DSC, and TGA. Membranes incorporating these functional fluoropolymers were prepared and the electrochemical properties (IEC, proton conductivity, swelling rates) were studied and discussed. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.