Proton Dissociation of Sulfonated Polysulfones: Influence of Molecular Structure and Conformation

The counterion condensation behavior of proton conducting sulfonated polysulfones has been investigated by combining electrophoretic NMR, pulsed magnetic field gradient NMR, and conductivity measurements on monomeric and polymeric samples with concentrations of ionic groups in the range where dissoc...

Full description

Saved in:
Bibliographic Details
Published inMacromolecules Vol. 48; no. 4; pp. 1134 - 1143
Main Authors Wohlfarth, Andreas, Smiatek, Jens, Kreuer, Klaus-Dieter, Takamuku, Shogo, Jannasch, Patric, Maier, Joachim
Format Journal Article
LanguageEnglish
Published American Chemical Society 24.02.2015
Subjects
Chemical Sciences
Kemi
Natural Sciences
Naturvetenskap
Online AccessGet full text

Cover

More Information
Summary:The counterion condensation behavior of proton conducting sulfonated polysulfones has been investigated by combining electrophoretic NMR, pulsed magnetic field gradient NMR, and conductivity measurements on monomeric and polymeric samples with concentrations of ionic groups in the range where dissociation is not complete (IEC = 4.55–7.04 mequiv g–1). In this regime, counterion condensation is shown to critically depend on details of the molecular structure, and all atom molecular dynamics (MD) simulations reveal the formation of well-defined ionic aggregates (e.g., triple ions). The corresponding global minima of the free energy are suggested to be the result of a delicate balance of the energetics involved in conformational changes, formation of ionic aggregates, and solvation. This goes beyond Manning’s counterion condensation theory and has important implications for the development of membranes with high ionic conductivity as needed for many electrochemical applications such as fuel cells and batteries.
ISSN:0024-9297
1520-5835
DOI:10.1021/ma502550f