Tandem one-pot synthesis of block copolymers for anion exchange membranes

The anion exchange membrane (AEM) suffered from poor mechanical properties and low ionic conductivity in fuel cells. Herein, a series of novel block fluorene-contained poly(arylene ether ketone)s backbones are synthesized by a tandem one-pot process and then grafted with alkyl chains to form comb-shaped structure for preparing AEMs. The one-pot synthesis of block copolymer avoids the multiple purifications of oligomers. The membranes' structure–property relationship is studied by changing the ratios of hydrophilic and hydrophobic segments. The designed comb-shaped structures grafted on fluorene-containing block backbones can widen the space between chains and form clear microphase separation patterns, as determined by atomic force microscope (AFM) and small angle x-ray scattering (SAXS). Hence, resulting AEMs have a high ionic conductivity (117.4 mS cm −1 , 80°C). Meanwhile, they also present low swelling rate (SR) from 12.76% to 18.51% at 30°C, 16.84% to 24.36% at 60°C, and 18.33% to 25.81% at 80°C. In addition, excellent mechanical properties, that is, an elongation at break of 29.63% and a tensile strength of 28.72 MPa, are achieved and showed the promise of as-fabricated AEMs in fuel cell applications.