Photocrosslinked fluorinated poly(aryl ether) anion exchange membrane for fuel cells

A series of gemini cationic fluorinated poly(aryl ether) anion exchange membranes (AEMs) with different photocrosslinking degrees were prepared. The AEMs with photosensitive structures can photocrosslink under UV irritation at room temperature in the swollen state. Atom force microscope (AFM) experiment confirmed that the membranes had obvious hydrophilic/hydrophobic microphase separation structure. The ion exchange capacities (IEC), water uptake, swelling rate, ionic conductivity, mechanical properties, and thermal stability of the membranes were also investigated. The IECs were in the range of 2.05-2.16 meq/g, but AEMs showed reasonable water uptakes and swelling ratio were 39.67 and 14.47% at 80 degrees C, respectively, due to the introduction of fluorine atoms. The crosslinked membranes still exhibited satisfying hydroxide conductivity with a maximum value of 133.44 mS/cm at 80 degrees C. It can be attributed to the formation of hydrophilic/hydrophobic microphase separation structure within the membrane and the development of a tremendous number of ion transport channels. The conductivity only decreased by 6.3% correspondingly after in 1 M NaOH at 60 degrees C for 7 days; indicating membranes have good alkaline stability.