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Fully aromatic ionomers with precisely sequenced sulfonated moieties for enhanced proton conductivity

Li, Xuefeng LU ; Paoloni, Francois LU ; Weiber, Annika LU ; Jiang, Zhen-Hua and Jannasch, Patric LU (2012) In Macromolecules 45(3). p.1447-1459
Abstract (Swedish)
Abstract in Undetermined

A series of six fully aromatic ionomers with precisely sequenced sulfonated sites along the polymer chains have been designed, prepared and characterized as proton-exchange membranes. Two straight-forward and efficient synthetic strategies based on Ullmann ether reactions and a Baeyer-Villiger rearrangement were devised to obtain bisphenol monomers with four or six phenylene units linked exclusively by ether bridges to avoid transetherification reactions. Polycondensations of these bisphenol monomers with mono- or disulfonated dihalide monomers gave high molecular weight poly(arylene ether), poly(arylene ether sulfone) and polyarylene ether ketone) homopolymers having microblock-like structures with... (More)
Abstract in Undetermined

A series of six fully aromatic ionomers with precisely sequenced sulfonated sites along the polymer chains have been designed, prepared and characterized as proton-exchange membranes. Two straight-forward and efficient synthetic strategies based on Ullmann ether reactions and a Baeyer-Villiger rearrangement were devised to obtain bisphenol monomers with four or six phenylene units linked exclusively by ether bridges to avoid transetherification reactions. Polycondensations of these bisphenol monomers with mono- or disulfonated dihalide monomers gave high molecular weight poly(arylene ether), poly(arylene ether sulfone) and polyarylene ether ketone) homopolymers having microblock-like structures with sulfonated moieties separated by monodisperse non-sulfonated oligo(ether) spacers. The nanoscale morphology and properties of solvent cast membranes were closely related to the nature of the oligo(ether) spacers. Small angle X-ray scattering (SAXS) measurements showed intense scattering and very narrow ionomer peaks with second-order features for the polymers with the six-ring spacers. This clearly indicated that the controlled ionic sequencing enabled self-assembly of ionic aggregates with a much higher degree of organization in relation to a corresponding aromatic ionomer with a statistical distribution of the sulfonate groups. At an identical acid content, the ionomers containing meta ether linkages had lower glass transition temperatures than the all-para materials, leading to a higher water uptake and proton conductivity of the former ionomers. A membrane with an ion exchange capacity (IEC) of 2.05 meq g-1 and containing exclusively para linkages reached the same level of proton conductivity as Nafion® at 100% relative humidity (RH), and also had an excellent dimensional stability in boiling water. Under reduced RH, the conductivity of this membrane greatly exceeded that of a membrane based on a statistical copolymer analogue with a similar ionic content. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
fuel cells, polymer electrolyte membranes, aromatic block copolymers, sequence-controlled polymerizations, SAXS
in
Macromolecules
volume
45
issue
3
pages
1447 - 1459
publisher
The American Chemical Society
external identifiers
  • wos:000300124200036
  • scopus:84863174723
ISSN
0024-9297
DOI
10.1021/ma201599p
language
English
LU publication?
yes
id
47446245-f173-4050-8194-e8e101257673 (old id 2295485)
alternative location
http://pubs.acs.org/doi/abs/10.1021/ma201599p
date added to LUP
2012-01-26 14:41:57
date last changed
2017-09-24 03:15:31
@article{47446245-f173-4050-8194-e8e101257673,
  abstract     = {<b>Abstract in Undetermined</b><br/><br>
A series of six fully aromatic ionomers with precisely sequenced sulfonated sites along the polymer chains have been designed, prepared and characterized as proton-exchange membranes. Two straight-forward and efficient synthetic strategies based on Ullmann ether reactions and a Baeyer-Villiger rearrangement were devised to obtain bisphenol monomers with four or six phenylene units linked exclusively by ether bridges to avoid transetherification reactions. Polycondensations of these bisphenol monomers with mono- or disulfonated dihalide monomers gave high molecular weight poly(arylene ether), poly(arylene ether sulfone) and polyarylene ether ketone) homopolymers having microblock-like structures with sulfonated moieties separated by monodisperse non-sulfonated oligo(ether) spacers. The nanoscale morphology and properties of solvent cast membranes were closely related to the nature of the oligo(ether) spacers. Small angle X-ray scattering (SAXS) measurements showed intense scattering and very narrow ionomer peaks with second-order features for the polymers with the six-ring spacers. This clearly indicated that the controlled ionic sequencing enabled self-assembly of ionic aggregates with a much higher degree of organization in relation to a corresponding aromatic ionomer with a statistical distribution of the sulfonate groups. At an identical acid content, the ionomers containing meta ether linkages had lower glass transition temperatures than the all-para materials, leading to a higher water uptake and proton conductivity of the former ionomers. A membrane with an ion exchange capacity (IEC) of 2.05 meq g-1 and containing exclusively para linkages reached the same level of proton conductivity as Nafion® at 100% relative humidity (RH), and also had an excellent dimensional stability in boiling water. Under reduced RH, the conductivity of this membrane greatly exceeded that of a membrane based on a statistical copolymer analogue with a similar ionic content.},
  author       = {Li, Xuefeng and Paoloni, Francois and Weiber, Annika and Jiang, Zhen-Hua and Jannasch, Patric},
  issn         = {0024-9297},
  keyword      = {fuel cells,polymer electrolyte membranes,aromatic block copolymers,sequence-controlled polymerizations,SAXS},
  language     = {eng},
  number       = {3},
  pages        = {1447--1459},
  publisher    = {The American Chemical Society},
  series       = {Macromolecules},
  title        = {Fully aromatic ionomers with precisely sequenced sulfonated moieties for enhanced proton conductivity},
  url          = {http://dx.doi.org/10.1021/ma201599p},
  volume       = {45},
  year         = {2012},
}