Synthesis and characterization of sulfonated polytriazoles utilizing 1,4‐bis(4‐azido‐2‐(trifluoromethyl)phenoxy)benzene for the proton exchange membrane applications

Abstract

The aromatic hydrocarbon‐based sulfonated polytriazoles have a reputation as a high‐performing polymer because of their excellent properties. This work demonstrates the synthesis of a new semi‐fluorinated diazide monomer, that is, 1,4‐bis(4‐azido‐2‐(trifluoromethyl)phenoxy)benzene (BATFB), and exploiting this compound a series of aromatic hydrocarbon‐based semi‐fluorinated sulfonated polytriazoles (BABPSSH‐60, −70, −80, −90) was synthesized utilizing the Cu(I)‐induced “click” cycloaddition polymerization reaction along with the sulfonated diazide monomer, 4,4′‐diazido‐2,2′‐stilbenesulfonic acid disodium salt tetrahydrate (DASSA) and the terminal dialkyne monomer, 4,4′‐(propane‐2,2′‐diyl)bis((prop‐2‐ynyloxy)benzene) (BPAAL). The structural analysis of those copolymers was completed by the FTIR and the NMR (1H and 13C) spectroscopic methods. Further, the degree of sulfonation (DS) and the ion exchange capacity (IEC) values of the copolymers were confirmed using the 1H NMR spectrums. They are readily soluble in respective solvents, and a light yellowish membrane was obtained using the solution casting procedure. These membranes demonstrated admissible mechanical and thermal stabilities, balanced water absorption properties, and reasonable chemical stability. The surface phase (SAXS, AFM) and bulk phase (TEM) morphological analysis proved the well‐separated phase morphology. The BABPSSH‐90 displayed a proton conductivity of 104 mS cm−1 at 90.

Synergistically Functionalized Pyridinyl- and Phosphine-Oxide-Based Semifluoro-Sulfonated Copolytriazole Membrane Preparation via “Click” Polymerization for Proton Exchange Membrane Applications

“…The PC value of 128 mS/cm at 90 °C is shown by the PYPOSSH-90 copolymer film, which is similar to or higher than several other previously reported sulfonated polymers (Table ) having comparable IEC values. The acid–base interaction of the −SO 3 H group and triazole unit of the polymer chain mainly transferred the proton along with the water molecules through the Grotthuss and Vehicular mechanisms. , Additionally, the presence of a −CF 3 group and pyridinyl- and phosphine-oxide-based moieties in the PYPOSSH-XX polymers synergistically tuned up the PC value by facilitating the proton conduction pathway. , Thus, the incorporation of pyridinyl- and phosphine-oxide-based units together in the polymeric backbone improved the PC values, which makes the PYPOSSH-XX copolymers suitable for PEMFC applications.…”