Poly(1,3‐phenylene‐5‐phosphonic Acid), a Fully Aromatic Polyelectrolyte with High Ion Exchange Capacity

Abstract

Poly(1,3‐phenylene‐5‐phosphonic acid) is characterized by a high density of functional groups (less than 100 g/mol equivalent weight per proton), good thermo‐oxidative stability up to at least 200 °C, the absence of a softening point, and a proton conductivity of more than 2 × 10–3 S/cm between 110 °C and 160 °C under water vapor. Based on these properties, this polymer appears to be well suited as proton conducting component in polymer electrolyte membranes.

Proton conducting membranes in fully anhydrous conditions at elevated temperature: Effect of Nitrilotris(methylenephosphonic acid) incorporation into Nafion- and poly(styrenesulfonic acid)

“…One possible approach to avoid leakage problem is tethering phosphonic acid groups to a polymer backbone. Poly(vinylphosphonic acid) [10] and analogous polymers [11,12] and poly(vinylphosphonic acid) / heterocycles composite [13] are just some examples. For these materials the best proton conductivities at elevated temperature in the nominally dry state were determined to be in the range 10 −4 -10 −2 S cm -1 .…”

Phosphonated polyimides: Enhancement of proton conductivity at high temperatures and low humidity

“…Although the IEC values of above 6 mequiv.g -1 is reported in the literature [36,43,44], the mechanical properties of polymer films is reported to be low due to the very high polarity of backbone [42,44]. At high degree of phosphonation, the polymers may even become water soluble [36] which necessitates other modifications such as, grafting [42] or blending [33] to achieve suitable membranes for FC applications.…”

Evaluation of carboxylic, phosphonic, and sulfonic acid protogenic moieties on tunable poly(meta‐phenylene oxide) ionomer scaffolds

“…Herein, we report the synthesis and analysis of proton conductivity of poly( m PO)s containing sulfonic, phosphonic, or carboxylic acid groups on otherwise identical polymer backbones. While some highly conductive sulfonic, carboxylic, and phosphonic acid‐functionalized polymers, MOFs, COFs, and hydrocarbon liquids have been synthesized, the lack of a versatile polymer platform has limited the direct comparison of these protogenic moieties toward rational PEM design. Herein, we explore how the identity of the acid moiety affects proton conduction.…”