The solvation and ion condensation properties for sulfonated polyelectrolytes in different solvents—a computational study

Abstract

In contrast to the broad knowledge about aqueous polyelectrolyte solutions, less is known about the properties in aprotic and apolar solvents. We therefore investigate the behavior of sulfonated polyelectrolytes in sodium form in the presence of different solvents via all-atom molecular dynamics simulations. The results clearly reveal strong variations in ion condensation constants and polyelectrolyte conformations for different solvents like water, dimethyl sulfoxide (DMSO) and chloroform. The binding free energies of the solvent contacts with the polyelectrolyte groups validate the influence of different solvent qualities. With regard to the ion condensation behavior, the numerical findings show that the explicit values for the condensation constants depend on the preferential binding coefficient as derived by the evaluation of Kirkwood-Buff integrals. Surprisingly, the smallest ion condensation constant is observed for DMSO compared to water, whereas in the presence of chloroform, virtually no free ions are present, which is in good agreement to the donor number concept. In contrast to the results for the low condensation constants, the sodium conductivity in DMSO is smaller compared to water. We are able to relate this result to the observed smaller diffusion coefficient for the sodium ions in DMSO.

Coarse-grained simulations of polyelectrolyte complexes: MARTINI models for poly(styrene sulfonate) and poly(diallyldimethylammonium)

“…As a crucial test case, we compared the chloride ion binding strength of the MARTINI model with the atomistic force field results. To estimate the chloride binding strength, the local preferential binding coefficient [17][18][19] between the nitrogen atom in the dimethylammonium group of PDADMA (denoted with the index 2) and the chloride ions (denoted as 3) can be calculated according to…”

Investigation of Solvent Type and Salt Addition in High Transference Number Nonaqueous Polyelectrolyte Solutions for Lithium Ion Batteries

“…13,14 Thus far, the only studies that have specifically investigated Li-ion transport through a nonaqueous polyelectrolyte solution have used dimethylsulfoxide (DMSO), a highly polar solvent that is able to solubilize highly charged macromolecules. [13][14][15] Unfortunately, DMSO is unsuitable for battery applications due to co-insertion of DMSO with lithium into graphite electrodes, effectively exfoliating the graphite and destroying the electrodes. 16 It is thus important to determine the fundamental design challenges remaining to create an HTNE composed of a lithium neutralized polyanion dissolved in the battery-relevant EC/DMC blend solvent.…”

Solvent effects of 1-ethyl-3-methylimidazolium acetate: solvation and dynamic behavior of polar and apolar solutes

“…This can be mostly explained by the overwhelming dominance of water in most biochemical processes as well as the still poorly understood hydrophobic and hydrophilic hydration behavior 49 . Indeed, promising approaches towards the full understanding of solvent behavior for macromolecular properties have been recently published [50][51][52] . However, it has to be stated that only a few aspects of solvophilic and solvophobic solvation properties are in general known [53][54][55] .…”