Shape transitions in supercritical CO2 microemulsions induced by hydrotropes

Craig James, Marios T Hopkins Hatzopoulos, C Yan, Gregory Smith, Shirin Alexander, Sarah E Rogers, Julian Eastoe*

*Corresponding author for this work

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

16 Citations (Scopus)
371 Downloads (Pure)


The ability to induce morphological transitions in water-in-oil (w/o) and water-in-CO2 (w/c) microemulsions stabilized by a trichain anionic surfactant 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2- sulfonate (TC14) with simple hydrotrope additives has been investigated. High-pressure small-angle neutron scattering (SANS) has revealed the addition of a small mole fraction of hydrotrope can yield a significant elongation in the microemulsion water droplets. For w/o systems, the degree of droplet growth was shown to be dependent on the water content, the hydrotrope mole fraction, and chemical structure, whereas for w/c microemulsions a similar, but less significant, effect was seen. The expected CO2 viscosity increase from such systems has been calculated and compared to related literature using fluorocarbon chain surfactants. This represents the first report of hydrotrope-induced morphology changes in w/c microemulsions and is a significant step forward toward the formation of hydrocarbon worm-like micellar assemblies in this industrially relevant solvent.

Original languageEnglish
Pages (from-to)96-102
Number of pages7
Issue number1
Early online date23 Dec 2013
Publication statusPublished - 14 Jan 2014


  • carbon-dioxide microemulsions
  • angle neutron-scattering
  • enhanced oil-recovery
  • CO2-philic surfactants
  • water
  • viscosity
  • micelles
  • dispersions
  • rods
  • sans


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