I am attempting to use sodium polyacrylate as a sodium transport mechanism in a sulfur-bromine cell. I can upset the sodium balance with sodium salts, but the contamination introduced by the non-metallic ion from that salt is unacceptable. Water is a solvent that can be ultimately coerced into a solution compatible with the acrylic polymer I wish to matrix the polyacrylate within.

I have tried (with no success) alcohols, acetone, and ketones. Are there non-aqueous solvents I should consider that suit my needs that I have not yet tried?

  • $\begingroup$ en.wikipedia.org/wiki/Polysulfide_bromide_battery $\endgroup$ – Mithoron Jul 27 '15 at 14:10
  • $\begingroup$ This is a link to the theoretical machine, but it has nothing to do with dissolving Sodium PolyAcrylate in other than salt laden water. $\endgroup$ – Aaron Scott Jul 27 '15 at 21:09
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    $\begingroup$ It's not useful for you but may be for guys who don't know about these batteries. More to the point, maybe solvents you used weren't polar enough - maybe sth like DMSO would work. $\endgroup$ – Mithoron Jul 27 '15 at 21:18
  • $\begingroup$ Interesting compound, this DSMO. Thanks for mentioning it, it is readily available and not very expensive. Worth a try! $\endgroup$ – Aaron Scott Jul 27 '15 at 22:24
  • $\begingroup$ Dissolve the powder in Methanol. You'll get your results $\endgroup$ – Ankit G Jan 2 '17 at 6:54

Sodium polyacrylate can locally organize solvent molecules to become soluble. Since the backbone is huge compared to water, the water aligns with its more positively charged end towards the carboxylate site while the sodium ions end up on the negative end of the water. I can't find the good papers right now, but if you search google scholar for using polyacrylic acid as a draw solute for forward osmosis you can dig way deeper into the mechanisms.

What this means practically is that you need really polar solvents that can line up with the ions. Wikipedia has a good page explaining solvent classification in more detail with a table of solvents including their dipole moment (quantifying the polarity). As suggested by Mithoron, DMSO seems to be a good option. Unfortunately, after that you start getting into much nastier solvents like acetonitrile and DMF.

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