Advanced

Anion conducting multiblock poly(arylene ether sulfone)s containing hydrophilic segments densely functionalized with quaternary ammonium groups

Weiber, Annika LU ; Meis, David and Jannasch, Patric LU (2015) In Polymer Chemistry 6(11). p.1986-1996
Abstract
We have prepared poly(arylene ether sulfone) multiblock copolymers with cationic blocks containing single dioxyphenylene rings functionalized with two, three or four quaternary ammonium (QA) roups in order to investigate the influence of the ionic concentration and distribution on the anionic conductivity.Precursor blocks were prepared by polycondensation of 4,4’-difluorodiphenyl sulfone and either di-, tri or tetramethylhydroquinone. Subsequently, these blocks were combined with precursor blocks prepared from 4,4’-dichlorodiphenyl sulfone and bisphenol A to form alternating multiblock copolymers with different block ratios. The benzylic methyl groups of the hydroquinone monomer units were then fully brominated using N-bromosuccinimide.... (More)
We have prepared poly(arylene ether sulfone) multiblock copolymers with cationic blocks containing single dioxyphenylene rings functionalized with two, three or four quaternary ammonium (QA) roups in order to investigate the influence of the ionic concentration and distribution on the anionic conductivity.Precursor blocks were prepared by polycondensation of 4,4’-difluorodiphenyl sulfone and either di-, tri or tetramethylhydroquinone. Subsequently, these blocks were combined with precursor blocks prepared from 4,4’-dichlorodiphenyl sulfone and bisphenol A to form alternating multiblock copolymers with different block ratios. The benzylic methyl groups of the hydroquinone monomer units were then fully brominated using N-bromosuccinimide. Quaternization with trimethylamine gave multiblock copolymers with extremely high ion exchange capacities (IECs) of the hydrophilic blocks, i.e., 3.2, 4.9, and 5.8 meq.g−1, respectively, in the Br− form. X-ray scattering and atomic force microscopy of the anion exchange membranes (AEMs) showed a distinct nanophase separation of the blocks. At a given IEC, the ionic conductivity was found to decrease with increasing number of QA groups per dioxyphenylene ring, probably because of limited ionic dissociation resulting from the close proximity of the QA groups. Thus, at a similar IEC, the conductivity of a block copolymer with tetra-functionalized rings reached the same level of conductivity as a corresponding polymer with randomly distributed QA groups, whereas a block copolymer with di-functionalized rings exceeded the conductivity of the latter polymer by a factor 4.2, despite a lower water uptake. These findings strongly highlight the importance of controlling and optimizing the local ionic concentration and distribution for highly anion conductive AEMs based on block copolymers. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Polymer Chemistry
volume
6
issue
11
pages
1986 - 1996
publisher
Royal Society of Chemistry
external identifiers
  • wos:000350642400012
  • scopus:84924058015
ISSN
1759-9954
DOI
10.1039/C4PY01588F
language
English
LU publication?
yes
id
960c3341-5224-481f-9f82-370dbc428635 (old id 4905127)
alternative location
http://pubs.rsc.org/en/content/articlelanding/2014/py/c4py01588f#!divAbstract
date added to LUP
2015-01-13 17:11:38
date last changed
2017-11-12 03:14:45
@article{960c3341-5224-481f-9f82-370dbc428635,
  abstract     = {We have prepared poly(arylene ether sulfone) multiblock copolymers with cationic blocks containing single dioxyphenylene rings functionalized with two, three or four quaternary ammonium (QA) roups in order to investigate the influence of the ionic concentration and distribution on the anionic conductivity.Precursor blocks were prepared by polycondensation of 4,4’-difluorodiphenyl sulfone and either di-, tri or tetramethylhydroquinone. Subsequently, these blocks were combined with precursor blocks prepared from 4,4’-dichlorodiphenyl sulfone and bisphenol A to form alternating multiblock copolymers with different block ratios. The benzylic methyl groups of the hydroquinone monomer units were then fully brominated using N-bromosuccinimide. Quaternization with trimethylamine gave multiblock copolymers with extremely high ion exchange capacities (IECs) of the hydrophilic blocks, i.e., 3.2, 4.9, and 5.8 meq.g−1, respectively, in the Br− form. X-ray scattering and atomic force microscopy of the anion exchange membranes (AEMs) showed a distinct nanophase separation of the blocks. At a given IEC, the ionic conductivity was found to decrease with increasing number of QA groups per dioxyphenylene ring, probably because of limited ionic dissociation resulting from the close proximity of the QA groups. Thus, at a similar IEC, the conductivity of a block copolymer with tetra-functionalized rings reached the same level of conductivity as a corresponding polymer with randomly distributed QA groups, whereas a block copolymer with di-functionalized rings exceeded the conductivity of the latter polymer by a factor 4.2, despite a lower water uptake. These findings strongly highlight the importance of controlling and optimizing the local ionic concentration and distribution for highly anion conductive AEMs based on block copolymers.},
  author       = {Weiber, Annika and Meis, David and Jannasch, Patric},
  issn         = {1759-9954},
  language     = {eng},
  number       = {11},
  pages        = {1986--1996},
  publisher    = {Royal Society of Chemistry},
  series       = {Polymer Chemistry},
  title        = {Anion conducting multiblock poly(arylene ether sulfone)s containing hydrophilic segments densely functionalized with quaternary ammonium groups},
  url          = {http://dx.doi.org/10.1039/C4PY01588F},
  volume       = {6},
  year         = {2015},
}