A hamburger-structure imidazolium-modified silica/polyphenyl ether composite membrane with enhancing comprehensive performance for anion exchange membrane applications

Abstract

With the intention of improving the comprehensive performance of anion exchange membranes (AEMs), a series of hamburger-structure AEMs based on triple-ammonium side chain poly(2,6-dimethyl-1,4-phenylene oxide) (TA-PPO) membrane were prepared. 1, 2-dimetylimidazolium-modified silica (Im-SiO2) was introducing to the surface of the TA-PPO membrane to fabricate a hamburger structure of Im-SiO2/TA-PPO membrane. The hamburger structure of the Im-SiO2/TA-PPO membrane is clearly observed by scanning electron microscope (SEM) and energy dispersive X-ray (EDX) linear scanning. Surprisingly, the Im-SiO2 layer on the surface of TA-PPO shows many valuable properties. Such as impressive ion conduction ability, water retaining capacity, and swelling resistance. Besides, the Im-SiO2 layer serves as a preserver to protect the TA-PPO membrane from being attacked by hydroxide and oxygen radical. Compared with TA-PPO membrane, the Im-SiO2/TA-PPO composite membrane exhibits the higher hydroxide conductivity and dimensional stability, and even higher alkaline stability and oxidation resistance. Typically, the Im-SiO2/TA-PPO composite membrane exhibits a maximum hydroxide conductivity of 105 mS/cm at 80 °C with a swelling ratio of 8.2%. Therefore, the hamburger structure of the Im-SiO2/TA-PPO membranes provides a new and reliable method to improve the comprehensive performance of AEM.