The European Physical Journal E

, Volume 4, Issue 2, pp 153–159 | Cite as

Bending free energy and spontaneous curvature for micelles and microemulsions with weak and strong surfactants

  • D. Vollmer
  • J. Vollmer


For mixtures of water, oil and non-ionic surfactant the temperature-induced phase separation of a droplet-phase microemulsion into a phase of smaller sized droplets coexisting with a water- or oil-rich phase is studied by differential-scanning microcalorimetry. A comparison of theoretical estimates and experimental findings for specific-heat measurements on mixtures containing different types of surfactants (weak and strong) support a broad range of applicability of an interfacial modeling (“Helfrich free energy”), provided a more general expression for the spontaneous curvature of the interface is considered than suggested so far. The model provides then a quantitative interfacial description even for the strongly curved diffuse interface of micelles of weak surfactants.

PACS. 82.70.-y Disperse systems – 05.70.Fh Phase transitions: general studies – 07.20.Fw Calorimetry 


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Copyright information

© EDP Sciences, Springer-Verlag, Società Italiana di Fisica 2001

Authors and Affiliations

  • D. Vollmer
    • 1
  • J. Vollmer
    • 2
  1. 1.Institut für Physikalische Chemie, Universität Mainz, Welder-Weg 11, 55099 Mainz, GermanyDE
  2. 2.Fachbereich Physik, Universität GH Essen, 45117 Essen, GermanyDE

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