The effects of counterion exchange on charge stabilization for anionic surfactants in nonpolar solvents

Gregory N. Smith, Paul Brown, Craig James, Roger Kemp, Asad Muhammad Khan, Tomás S. Plivelic, Sarah E. Rogers, Julian Eastoe*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

20 Citations (Scopus)
285 Downloads (Pure)

Abstract

Hypothesis: Sodium dioctylsulfosuccinate (Aerosol OT or NaAOT) is a well-studied charging agent for model poly(methyl methacrylate) (PMMA) latexes dispersed in nonpolar alkane solvents. Despite this, few controlled variations have been made to the molecular structure. A series of counterion-exchanged analogs of NaAOT with other alkali metals (lithium, potassium, rubidium, and cesium) were prepared, and it was expected that this should influence the stabilization of charge on PMMA latexes and the properties of the inverse micelles. Experiments: The electrophoretic mobilities of PMMA latexes were measured for all the counterion-exchanged AOT analogs, and these values were used to calculate the electrokinetic or ζ potentials. This enabled a comparison of the efficacy of the different surfactants as charging agents. Small-angle scattering measurements (using neutrons and X-rays) were performed to determine the structure of the inverse micelles, and electrical conductivity measurements were performed to determine the ionized fractions and Debye lengths. Findings: Sodium AOT is a much more effective charging agent than any of the other alkali metal AOTs. Despite this, the inverse micelle size and electrical conductivity of NaAOT are unremarkable. This shows a significant non-periodicity in the charging efficiency of these surfactants, and it emphasizes that charging particles in nonpolar solvents is a complex phenomenon.

Original languageEnglish
Pages (from-to)316-322
Number of pages7
JournalJournal of Colloid and Interface Science
Volume465
Early online date2 Dec 2015
DOIs
Publication statusPublished - 1 Mar 2016

Keywords

  • Electrophoresis
  • Nonpolar solvents
  • Polymer latexes
  • Small-angle scattering
  • Surfactants

Fingerprint Dive into the research topics of 'The effects of counterion exchange on charge stabilization for anionic surfactants in nonpolar solvents'. Together they form a unique fingerprint.

Cite this