Fig. 3: Physical properties of AEMs.

a OH⁻ and b Cl⁻ conductivity of different AEMs as a function of temperature along with the picture of PFTP-13 membranes after testing at 98 °C. PFBP-14 and PFBP-0 membranes showed poor dimensional stability at high temperatures, and thus it was difficult to measure their OH⁻ conductivities over 90 °C. c, d A picture of transparent PFTP-13 membranes 13.5 × 22.5 cm in size. e SEM image of a cross-section of PFTP-13 membrane with a thickness of ~15 µm. f The TS and EB of AEMs in I⁻ form and commercial FAA-3-20 membranes at room temperature. Compared to the present PFTP-0 AEMs (TS: 71 MPa, EB: 45.7%, YM: 1.2 GPa) and reported PAP-TP-x AEMs (TS: 67 MPa and EB:117%)¹⁷, PFTP-13 AEMs exhibit much higher TS and YM but lower EB, indicating that the PFTP-13 AEMs have a higher deformation resistance. g The tensile strength and elongation at break of PFTP-13 and PFTP-0 membranes at different temperatures and types. PFTM-13 is PFTP-14 before quaternization, whereas PFTP-13-I⁻ and PFTP-13-OH⁻ are in I⁻ and OH⁻ forms, respectively. PFTP-13 AEMs maintain their mechanical properties at 60 °C. Compared to Peng et al. ’s PFTP-0 AEMs³⁶ (TS: 35 MPa and EB: 40%), the present PFTP-13 and PFTP-0 AEMs (TS: > 50 MPa and EB: ~60%) in OH⁻ form exhibit much higher mechanical properties due to their higher intrinsic viscosity.