Alkaline Stability Study of Quaternary Phosphonium Cations

摘要

The cationic group is the functional heart of hydroxide exchange membranes (HEMs), controlling fundamental properties such as stability, conductivity and solubility. Ammonium cations1,2, exemplified by benzyl trimethyl ammonium (BTMA), have long been used for HEMs, establishing the cation standard for HEMs. Recently, we introduced the phosphonium cation (tris(2,4,6-trimethoxyphenyl) phosphonium (TPQP))3-6 to polymersulfone backbone and effectively improved the alkaline stability, hydroxide conductivity and solubility of HEMs. We found that in membrane form, TPQP based HEMs show better alkaline stability than BTMA analogs.