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. By using a tandem one‐pot process, a series of block copolymers are synthesized and then grafted with alkyl chains to form comb‐shaped structure for preparing anion exchange membranes.