Studies of sulfonated polyphenylene containing fluorine moiety via nickel catalyzed C–C coupling polymerization

• We synthesize sulfonated polyphenylene containing fluorine moieties.
• We control sulfonation level by reaction time using fuming sulfuric acid.
• Increasing sulfonation level increases proton conductivity.
• Membranes have good performance with chemically stability.

The synthesis of polyphenylenes containing fluorine moiety (PPTF), their functionalization with sulfonic acid groups, and the measurement of apposite parameters for PEMs are described. The polymers were prepared by Ni-catalyzed carbon–carbon coupling reaction of -(2,2,2-trifluoro-1-phenylethylidene)-bis(4-chlorobenzene) (TFPECB) and 2,5-dichlorobenzophenone, followed by sulfonation reaction with chlorosulfuric acid. These polymers have all carbon–carbon linkages without any ether linkage on the polymer backbone, which was not attacked by nucleophiles (H2O, hydrogen peroxide, hydroxide anion and radical), and sulfuric acid groups were selectively attached to the side phenyl rings of the TFPECB unit. A series of membranes was studied by 1H NMR spectroscopy, ion exchange capacity (IEC), water uptake, and proton conductivity. The membranes' degradation was tested with Fenton reagent and compared with normal sulfonated poly(ether sulfone)s and Nafion.