Anion exchange membranes (AEMs) are a promising class of materials for applications that require selective ion transport, such as fuel cells, water purification, and electrolysis devices. Studies of structure–morphology–property relationships of ion-exchange membranes revealed that block copolymers exhibit improved ion conductivity and mechanical properties due to their microphase-separated morphologies with well-defined ionic domains. While most studies focused on symmetric diblock or triblock copolymers, here, the first example of a midblock quaternized pentablock AEM is presented. A symmetric ABCBA pentablock copolymer was functionalized to obtain a midblock brominated polymer. Solution cast films were then quaternized to obtain AEMs with resulting ion exchange capacities (IEC) ranging from 0.4 to 0.9 mmol/g. Despite the relatively low IEC, the polymers were highly conductive (up to 60 mS/cm Br− at 90 °C and 95%RH) with low water absorption (<25 wt %) and maintained adequate mechanical properties in both dry and hydrated conditions. X-ray scattering and transmission electron microscopy (TEM) revealed formation of cylindrical non-ionic domains in a connected ionic phase.
|Original language||English (US)|
|Number of pages||11|
|Journal||Journal of Polymer Science, Part B: Polymer Physics|
|State||Published - Apr 1 2017|
Bibliographical notePublisher Copyright:
© 2017 Wiley Periodicals, Inc.
Copyright 2017 Elsevier B.V., All rights reserved.
- anion exchange membrane
- block copolymers
- conducting polymers
- inverse morphology
- ion conductivity
- mechanical properties
- mechanically robust
- pentablock copolymer