Nano-spheres stabilized poly(vinyl phosphonic acid) as proton conducting membranes for PEMFCs

•P4VP nano-spheres were used to stabilize PVPA as proton conducting membranes.•The dimensional stability was dramatically improved after blending with P4VP-NS.•The effect of acid–base interaction on proton conduction was disclosed.•The blends show high proton conductivity above 10−2 S cm−1 under humid conditions.•The thermal stability was improved by acid–base interactions in the blends.

Poly(4-vinyl pyridine) nano-spheres (P4VP-NS) stabilized poly(vinyl phosphonic acid) (PVPA) membranes were prepared as proton conducting membranes for fuel cells. The acid–base interactions between P4VP-NS and PVPA were utilized to improve the dimensional and thermal stability of PVPA. In this work, the effects of acid–base interactions on proton conductivity and thermal stability were quantitatively determined and discussed based on the results of 1H magic-angle-spin NMR (1H MAS NMR), Fourier transfer infrared spectroscopy (FTIR) and impedance spectroscopy measurements.