High Performance Ion Exchange Membranes Prepared via Direct Polyacylation of Racemic and (S)‐1,1′‐Binaphthyl‐Based Cationic/Anionic Monomers

摘要

Abstract Side‐chain‐type sulfonated/quaternized aromatic polyelectrolytes with precisely controlled contents of ionized groups are successfully synthesized via direct polyacylation of sulfonated/quaternized monomers based on 2,2′‐dihydroxy‐1,1′‐binaphthyl (DHBN). Both proton exchange membranes (PEMs) and anion exchange membranes (AEMs) of the corresponding polyelectrolytes exhibit outstanding properties. Proton conductivity (116?mS?cm ?1 at 30?°C) higher than Nafion 115 for the PEMs and OH – conductivity (28.5–53.7?mS?cm ?1 at 30?°C) comparable to Tokuyama A901 for the AEMs are accomplished. In addition, the AEMs can withstand 60?days’ aging in 1?mol?L ?1 NaOH at 60?°C without degradation, as proved by 1 H NMR. More intriguingly, when starting from optically active ( S )‐DHBN instead of racemic DHBN, an enhancement in proton conductivity of PEMs is observed for the first time, which opens a new door to optically active ion exchange membranes.