Sulfonated Poly(aryl sulfone)s Containing Ferrous and Ferric Ion Scavenger 1H-Imidazo[4,5-F][1,10]-phenanthroline Groups for Highly Durable Proton Exchange Membranes

Proton exchange membranes prepared from poly(aryl sulfone)sstillneed to overcome the drawbacks of chemical stability in acidic environmentsand low electrical conductivity due to water loss at high temperatures.Herein, we synthesized densely sulfonated poly(aryl sulfone) protonexchange membranes containing a 1H-imidazo[4,5-F][1,10]-phenanthrolinemoiety on the side chain with a metal ion coordination function. Thecoordination of 1H-imidazo[4,5-F][1,10]-phenanthroline groups to metalions can effectively prevent the formation of (& BULL;)OHradicals from homolytic cleavage of H2O2 catalyzedby metal ions. Since the conditions for the continuous formation of (OH)-O-& BULL; radicals are fundamentally eliminated, the antioxidantstability of the membrane material is greatly improved. Mesoscalemicroscopic simulations showed that 1H-imidazo[4,5-F][1,10]-phenanthrolinehas the effect of inducing phase separation, endowing the proton exchangemembrane with a larger hydrophilic structural domain and possiblyconstructing a better connected channel for proton transport. Notably,these membranes can efficiently capture the Fe2+ and Fe3+ ions to form stable [Fe(phen)(3)](2+) and[Fe(phen)(3)](3+) interconnection points, respectively,which could not only enforce the water retention and the mechanicalproperties of the membranes but also serve as a catalyzed point toprevent H2O2 from undergoing homolytic cleavageand forming (OH)-O-& BULL; radicals.

Automated summary

By synthesizing densely sulfonated poly(aryl sulfone) proton exchange membranes containing 1H-imidazo[4,5-F][1,10]-phenanthroline with metal ion coordination function, the formation of (•)OH radicals from the cleavage of H2O2 catalyzed by metal ions can be effectively prevented. The 1H-imidazo[4,5-F][1,10]-phenanthroline can induce phase separation and create a larger hydrophilic domain, which improves the antioxidant stability and possibly establishes a better connected channel for proton transport. The formation of stable interconnection points through the capture of Fe2+ and Fe3+ ions also enhances water retention and mechanical properties while preventing the generation of (OH)-O-• radicals.