Characteristics of polyethersulfone/sulfonated polyimide blend membrane for proton exchange membrane fuel cell.

Solution-cast membranes from sulfonated polyimide (SPI) and its blend were prepared from polyethersulfone (PES) and SPI. The water uptake and swelling were tested and compared between the SPI membrane and the four kinds of blend membranes. Through comparison of the stability of the membranes, we concluded that the PES could greatly increase the stability of the whole membrane and restrict the swelling. However, the PES did not decrease the water uptake very much. We also compared the fuel cell performance with different membranes. The performance was decreased when the content of the PES in the blend membrane increased. The loss of the fuel cell performance with the blend membranes did not decrease very much before the content of the PES was exceeded 20%. It was prospected that the blend membrane could increase the stability of the SPI and, more importantly, even replace the commercial Nafion membranes.