LAUSR

Phosphonic acid functionalized siloxane cross-linked with 3-glycidoxypropyltrimethoxysilane (GPTMS) grafted polybenzimidazole (PBI) membranes are prepared by sol–gel process. The structure of the membranes is characterized by Fourier-transform infrared spectroscopy and X-ray diffraction spectroscopy. SEM images of the membranes show that the membranes are homogeneous and compact. The cross-linked membranes exhibit excellent thermal stability, chemical stability and mechanical property. The proton conductivity of the cross-linked membranes increases by an order of magnitude over range of 20°C to 160°C under anhydrous condition, which can reach 3.15 × 10−2 S cm−1 at 160°C under anhydrous condition. The activation energy of proton conductivity for membranes decreases with increase of PBI, because the formation of hydrogen bond network between the phosphonic acid and the imidazole ring can enhance the continuity of hydrogen bond in the membrane. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 133, 44818.