%0 Journal Article
%A S. S Piril Ertem
%A Benjamin R Caire
%A Tsung-Han Tsai
%A Di Zeng
%A Melissa A Vandiver
%A Ahmet Kusoglu
%A Soenke Seifert
%A Ryan C Hayward
%A Adam Z Weber
%A Andrew M Herring
%A E. E Bryan Coughlin
%A Matthew W Liberatore
%B Journal of Polymer Science Part B: Polymer Physics
%D 2017
%G eng
%N 7
%P 612 - 622
%R 10.1002/polb.24310
%T Ion transport properties of mechanically stable symmetric ABCBA pentablock copolymers with quaternary ammonium functionalized midblock
%V 55
%8 01/2017
%! J. Polym. Sci. Part B: Polym. Phys.
%X <p><span>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</span><span>−</span><span>at 90 °C and 95%RH) with low water absorption (&lt;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.&nbsp;</span></p>