Blend proton exchange membranes with high performance based on sulfonated poly(arylene ether phosphine oxide)s and poly(vinylidene fluoride)

Abstract

A series of blend membranes based on sulfonated poly(arylene ether phosphine oxide)s (sPEPOF) and poly(vinylidene fluoride) (PVDF) were prepared and studied. The miscibility and thermal properties of blend membranes were evaluated. The morphologies were investigated by atomic force microscope. The results demonstrated that the blend membranes exhibited good compatibility and high thermal stability. The microstructures of blend membranes could be adjusted by introducing hydrophobic PVDF, thus improving the properties of membranes. Additionally, a suitable content of PVDF was in favor of promoting proton conductivity, oxidative stability, restraining water swelling, and methanol permeability. For example, the blend membrane containing 5% weight content of PVDF displayed a proton conductivity of 0.135 S cm−1, which was higher than those of the pristine sPEPOF membrane (0.124 S cm−1) and Nafion 117 (0.114 S cm−1) at 80 °C and 100% relative humidity. Meanwhile, it showed a lower swelling than that of Nafion 117, and its methanol permeability was about one-fortieth that of Nafion 117. Besides, the oxidative stability was also remarkably improved compared to the pristine sPEPOF membrane. Therefore, the achieved blend membranes exhibited excellent application prospect.