New crosslinked sulfonated polytriazoles: Proton exchange properties and microbial fuel cell performance

Abstract

The synthesis, characterization and establishment of the structure-property relationship of a series of new semifluorinated sulfonated polytriazoles (PTCTSH-XX) with varying degrees of sulfonation are described. The polymers were synthesized by the click polymerization reaction of a mixture of two diazide monomers, the non-sulfonated diazide monomer 4,4-bis[3-trifluoromethyl-4(4-azidophenoxy) phenyl]benzene (TAZ) and the sulfonated diazide monomer 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt (SAZ), with an equimolar amount of the dialkyne monomer 3,5-bis(prop-2-ynyloxy)benzoic acid (BPBA). The polytriazoles were characterized by 1H and 13C NMR spectroscopy. All the polymers showed good solubility in selected polar aprotic organic solvents along with excellent film forming ability. The TEM micrographs of these polymers exhibited a uniformly phase separated morphology. The polymers showed very high proton conductivity and the values were within the range of 15–67 mS cm−1 at 30 °C, 38–163 mS cm−1 at 80 °C and 42–176 mS cm−1 at 90 °C in hydrated condition. The pristine polymers were crosslinked with poly(vinyl alcohol) and their PEM properties were also investigated. The crosslinked films showed lower water uptake and dimensional swelling and improved oxidative stability in comparison to the pristine membranes. The microbial fuel cell performance of both pristine and crosslinked membranes was also investigated.