Proton-conducting membranes amphoteric polymers

The PBI derivatives possess both proton acceptor and proton donor sites. They are thus chemically amphoteric with pATa and pA aH values typically of around 13 and 5, respectively [24, 25]. However, the polybenzimidazoles are more basic than water, and thus commonly referred to as basic polymers. They show high affinity towards polar compounds such as hquid acids and bases, which are used as dopants to provide ion conductivity to the membrane. Depending on the chemical nature and the concentration of the dopant it results in partial or full protonation or... 

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