Perfluoropolyether (PFPE)-Based Vitrimers with Ionic Conductivity

Ion-conducting low-T-g perfluoropolyether (PFPE)-based vitrimers were obtained via thermally initiated polyaddition and in situ N-alkylation in the presence of a fluorinated cross-linker. Both reactions were quantified by differential scanning calorimetry (DSC) employing the Vyazovkin method (74 +/- 1 kJ mol(-1) for the polyaddition and 140 kJ mol(-1) for the N-alkylation). The viscous flow activation energy was found to be 161 +/- 23 kJ mol(-1), in good correlation with the activation energy calculated by DSC for the N-alkylation. The creep behavior at elevated temperature is typical of a viscoelastic liquid and the relaxation times range from 2.5 h at 170 degrees C to 4 min at 210 degrees C. The topology freezing transition temperatures found via thermal creep experiment and relaxometry were in absolute agreement (ca. 110 degrees C). The network is stable under acidic and basic environments and can recover its mechanical properties after two recyclings. Three samples were prepared by varying the cross-linker loading, and the most stable displays a T-d(5%) of 293 degrees C under nitrogen and a water contact angle of 136 degrees. Ionic conductivities for these nondoped materials range from 0.5 X 10(-6) to 1.1 X 10(-6) S cm(-1) at 27 degrees C.