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Perfluoropolyether (PFPE)-Based Vitrimers with Ionic Conductivity

Lopez, Gérald, Granado, Lérys, Coquil, Gaël, Lárez-Sosa, Andrés, Louvain, Nicolas, Améduri, Bruno
Macromolecules 2019 v.52 no.5 pp. 2148-2155
activation energy, alkylation, differential scanning calorimetry, freezing, liquids, mechanical properties, nitrogen, temperature, viscoelasticity
Ion-conducting low-Tg 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 °C to 4 min at 210 °C. The topology freezing transition temperatures found via thermal creep experiment and relaxometry were in absolute agreement (ca. 110 °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 Td⁵% of 293 °C under nitrogen and a water contact angle of 136°. Ionic conductivities for these nondoped materials range from 0.5 × 10–⁶ to 1.1 × 10–⁶ S cm–¹ at 27 °C.