Interfacial tension in aqueous biopolymer–surfactant mixtures

Fotios Spyropoulos, Ping Ding, WJ Frith, Ian Norton, B Wolf, Andrzej Pacek

Research output: Contribution to journalArticle

16 Citations (Scopus)


The current study offers a first insight into the interfacial properties of pullulan-sodium dodecyl sulphate (SDS) aqueous two-phase systems (ATPS) in the presence of sodium chloride (NaCl). The effect of composition on the interfacial tension (sigma) in these ATPS was investigated over a wide range of pullulan, SDS and NaCl concentrations. An increase in the interfacial tension was observed with increasing pullulan and SDS concentrations and a small increase was also observed as the NaCl concentration was increased. In both cases the interfacial tension increases were closely related to the phase behaviour of these systems; as a consequence of increasing the pullulan, SDS and/or NaCl concentrations, the system moves further away from the critical point. In all systems interfacial tensions (of the order of muN/m) were comparable with those reported for polymer-polymer ATPS. Interfacial tensions sigma can be well correlated with the difference in pullulan and SDS concentrations between the phases (DeltaC pul and DeltaC SDS) and also the tie-line length (TLL); all yield straight lines on a log-log scale.
Original languageEnglish
Pages (from-to)604-610
Number of pages7
JournalJournal of Colloid and Interface Science
Issue number2
Publication statusPublished - 15 Jan 2008


  • pullulan
  • SDS
  • polymer-surfactant mixtures
  • retracting drop method
  • NaCl
  • interfacial tension
  • aqueous two-phase systems


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