聚(芴-亚烷基)系列阴离子交换膜的形态和水传输对链结构的依赖《Macromolecules》

Chain Architecture Dependence of Morphology and Water Transport in Poly(fluorene alkylene)-Based Anion-Exchange Membranes

Xiaofeng Li, Kuan Yang, Zimo Wang, Yaohan Chen, Yonggang Li, Jing Guo, Jifu Zheng*, Shenghai Li*, and Suobo Zhang

Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun130022, China

University of Science and Technology of China, Hefei230026, China

Macromolecules 2022, XXXX, XXX, XXX-XXX

Publication Date: November 17, 2022

https://doi.org/10.1021/acs.macromol.2c01488

Abstract

Main-chain non-ether anion-exchange membranes (AEMs) have become a research hotspot in recent years because of their ease of preparation and excellent alkaline stability. However, owing to the limitations of the types of monomers and polymerization mechanisms, preparing main-chain non-ether AEMs with controllable morphology remains challenging. Herein, seven poly(fluorene alkylene) membranes, including random and block-structured membranes with different quaternary ammonium (QA) group distributions on the side chains, with the same ion-exchange capacity (IEC) were designed via superacid-catalyzed polymerization. The properties of the as-synthesized membranes were characterized, and the water-transport mechanism has been discussed in relation to the morphology of the membranes. The formed bicontinuous phase structure based on block biphenyl units possessed multidirectional ion channels and distinct ion clusters favorable to water molecule movement. The conductivity of the optimized membrane with a block biphenyl structure reached 208 mS cm–1 at 80 °C, and the peak power density of an H2/O2 fuel cell based on the as-prepared membrane was 0.92 W cm–2. The reported approach is effective in balancing the content of free and bound water within the membrane, generating maximum hydroxide mobility and water transport suitable for high-performance AEM fuel cells. This study highlights the significance of regulating the block structure and adjusting the segment distribution in AEMs to tune their morphologies and provides an innovative design approach for constructing high-performance AEMs.

SUBJECTS:

• Anions,

• Copolymers,

• Electrical conductivity,

• Membranes,

• Polymers