Comb-shaped anion exchange membrane with segmented hydrophilic/hydrophobic side chain

Abstract

A flexible hydrophilic chain segment with ether bonds and a long hydrophobic tail chain with multiple carbon atoms are designed and grafted on the same side of the polymer backbone, which can not only improve the alkaline stability by preventing the benzyl carbon from being attacked by OH-, but also reduce the hydration degree of the membrane, giving it excellent conductivity, alkaline stability and low swelling ratio. These results show that the prepared anion exchange membranes (AEMs) with a hydrophilic chain segment containing 2 ether bonds exhibits the best overall performance. Its ionic conductivity can reach 90.4 mS cm−1 at 80 °C, the swelling ratio is less than 8%, the tensile strength can reach 14.5 MPa, and the elongation at break is 79.0%. Even after being soaked under alkaline conditions for 672 h, the conductivity of the original membrane still remains over 85%. The peak power density of the fuel cell using this AEM can reach as high as 582 mW cm−2. The segmented hydrophilic and hydrophobic side chain proposed in this work provides a novel idea to design the AEM materials and improve the performance of anion exchange membrane fuel cell.