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Title: Ion transport properties of mechanically stable symmetric ABCBA pentablock copolymers with quaternary ammonium functionalized midblock

Abstract

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 Br2 at 90 8C and 95%RH) with low water absorption (<25 wt %) and maintained adequate mechanical properties in both dry and hydrated conditions. Xray scattering and transmission electron microscopy (TEM) revealed formation of cylindrical non-ionic domains in a connected ionic phase.

Authors:
 [1];  [2];  [1];  [1];  [2];  [3];  [3];  [1];  [3];  [2];  [1];  [4]
  1. Department of Polymer Science and Engineering, University of Massachusetts Amherst, 120 Governors Drive Amherst Massachusetts 01003
  2. Department of Chemical and Biological Engineering, Colorado School of Mines, Golden Colorado 80401
  3. Energy Conversion Group, Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley California 94720
  4. Department of Chemical Engineering Department, University of Toledo, 2801 W Bancroft Street MS305 Toledo Ohio 43606
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); Argonne National Laboratory - Advanced Photon Source; US Army Research Office (ARO)
OSTI Identifier:
1395845
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Polymer Science. Part B, Polymer Physics; Journal Volume: 55; Journal Issue: 7
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; anion exchange membrane; block copolymers; conducting polymers; inverse morphology; ion conductivity; ionomers; mechanical properties; mechanically robust; morphology; pentablock copolymers

Citation Formats

Ertem, S. Piril, Caire, Benjamin R., Tsai, Tsung-Han, Zeng, Di, Vandiver, Melissa A., Kusoglu, Ahmet, Seifert, Soenke, Hayward, Ryan C., Weber, Adam Z., Herring, Andrew M., Coughlin, E. Bryan, and Liberatore, Matthew W. Ion transport properties of mechanically stable symmetric ABCBA pentablock copolymers with quaternary ammonium functionalized midblock. United States: N. p., 2017. Web. doi:10.1002/polb.24310.
Ertem, S. Piril, Caire, Benjamin R., Tsai, Tsung-Han, Zeng, Di, Vandiver, Melissa A., Kusoglu, Ahmet, Seifert, Soenke, Hayward, Ryan C., Weber, Adam Z., Herring, Andrew M., Coughlin, E. Bryan, & Liberatore, Matthew W. Ion transport properties of mechanically stable symmetric ABCBA pentablock copolymers with quaternary ammonium functionalized midblock. United States. doi:10.1002/polb.24310.
Ertem, S. Piril, Caire, Benjamin R., Tsai, Tsung-Han, Zeng, Di, Vandiver, Melissa A., Kusoglu, Ahmet, Seifert, Soenke, Hayward, Ryan C., Weber, Adam Z., Herring, Andrew M., Coughlin, E. Bryan, and Liberatore, Matthew W. Tue . "Ion transport properties of mechanically stable symmetric ABCBA pentablock copolymers with quaternary ammonium functionalized midblock". United States. doi:10.1002/polb.24310.
@article{osti_1395845,
title = {Ion transport properties of mechanically stable symmetric ABCBA pentablock copolymers with quaternary ammonium functionalized midblock},
author = {Ertem, S. Piril and Caire, Benjamin R. and Tsai, Tsung-Han and Zeng, Di and Vandiver, Melissa A. and Kusoglu, Ahmet and Seifert, Soenke and Hayward, Ryan C. and Weber, Adam Z. and Herring, Andrew M. and Coughlin, E. Bryan and Liberatore, Matthew W.},
abstractNote = {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 Br2 at 90 8C and 95%RH) with low water absorption (<25 wt %) and maintained adequate mechanical properties in both dry and hydrated conditions. Xray scattering and transmission electron microscopy (TEM) revealed formation of cylindrical non-ionic domains in a connected ionic phase.},
doi = {10.1002/polb.24310},
journal = {Journal of Polymer Science. Part B, Polymer Physics},
number = 7,
volume = 55,
place = {United States},
year = {Tue Feb 07 00:00:00 EST 2017},
month = {Tue Feb 07 00:00:00 EST 2017}
}
  • Imidazolium and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone)s were synthesized successfully with the same degree of cationic functionalization and identical polymer backbones for a comparative study of anion exchange membranes (AEMs) for solid-state alkaline membrane fuel cells (AMFCs). Both anion exchange membranes were synthesized using a new methyl-containing monomer that avoided the use of toxic chloromethylation reagents. The polymer chemical structures were confirmed by H-1 NMR and FTIR. The derived AEMs were fully characterized by water uptake, anion conductivity, stability under aqueous basic conditions, and thermal stability. Interestingly, both the cationic groups and the polymer backbone were found to bemore » degraded in 1 M NaOH solution at 60 degrees C over 48 h as measured by changes of ion exchange capacity and intrinsic viscosity. Imidazolium-functionalized poly(fluorenyl ether ketone sulfone)s had similar aqueous alkaline stability to quaternary ammonium-functionalized materials at 60 degrees C but much lower stability at 80 degrees C. This work demonstrates that quaternary ammonium and imidazolium cationic groups are not stable on poly(arylene ether sulfone) backbones under relatively mild conditions. Additionally, the poly(arylene ether sulfone) backbone, which is one of the most common polymers used in ion exchange membrane applications, is not stable in the types of molecular configurations analyzed.« less
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  • Midblock-sulfonated triblock copolymers afford a desirable opportunity to generate network-forming amphiphilic materials that are suitable for use in a wide range of emerging technologies as fuel-cell, water-desalination, ion-exchange, photovoltaic, or electroactive membranes. Employing a previously reported synthetic strategy wherein poly( p- tert-butylstyrene) remains unreactive, we have selectively sulfonated the styrenic midblock of a poly( p- tert-butylstyrene- b-styrene- b- p- tert- butylstyrene) (TST) triblock copolymer to different extents. Comparison of the resulting sulfonated copolymers with results from our prior study provides favorable quantitative agreement and suggests that a shortened reaction time is advantageous. An ongoing challenge regarding the morphological development ofmore » charged block copolymers is the competition between microphase separation of the incompatible blocks and physical cross-linking of ionic clusters, with the latter often hindering the former. Here, we expose the sulfonated TST copolymers to solvent-vapor annealing to promote nanostructural refinement. Furthermore, the effect of such annealing on morphological characteristics, as well as on molecular free volume, is explored.« less
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  • No abstract prepared.