Poly(acrylic acid) containing multi-benzimidazole units: A simple approach to obtain polymer with proton donor–acceptor system

The present work demonstrates a simple approach to prepare a unique polymer system based on poly(acrylic acid) containing multi-benzimidazole groups. The polymer provides not only the proton donor–acceptor system but also the hydrogen bond network which is essential in proton transfer under anhydrous system. The content of branched tri-benzimidazole for only 2.8 mol% significantly improves proton conductivity of the PAA for almost 50 times at high operating temperature (above 120 °C) indicating an efficient proton transfer through the chain movement of proton donor–acceptor units. The present work, for the first time, shows the simple synthesis of polymer containing multi-benzimidazole units and the proton transfer efficiency under a good balance of hydrogen bond network and polymer chain mobility.