Colloid and Polymer Science

, Volume 273, Issue 3, pp 257–262 | Cite as

Mixtures of branched non-ionic oligo-oxyethylene surfactants in aqueous solutions — the effect of molecular geometry on LC phase behaviour 4

  • K. Kratzat
  • C. Stubenrauch
  • H. Finkelmann
Original Contribution


The LC phase behavior of ternary mixtures of the two corresponding branched non-ionic surfactants 1,3-bis-(methoxy-tetraoxyethylene)-2-propoxy-tetradecane (Y-surfactant) and 1,3-bis-(heptyloxy)-2-propoxyoctaoxyethylene mono-methyl ether (V-surfactant) and water were studied by polarizing microscopy. The two branched surfactants, which have different molecular geometries but nearly the same hydrophilic-lipophilic volume ratio, exhibit extremely different phase behavior in binary surfactant/water systems. For the ternary mixtures of Y- and V-surfactant and water we found-according to established packing models-a continuous stabilization of the cubic and hexagonal phases and a destabilization of the lamellar phase with increasing amount of Y-surfactant. On the other hand, we observed a thermal stabilization of the lamellar phase. The maximal transition temperatures of the lamellar phase pass a maximum with increasing amount of Y-surfactant.

Key words

Non-ionic surfactants oligo-oxyethylene surfactants mixtures of surfactants lyotropic liquid crystal phase behavior 


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Copyright information

© Steinkopff Verlag 1995

Authors and Affiliations

  • K. Kratzat
    • 1
  • C. Stubenrauch
    • 1
  • H. Finkelmann
    • 1
  1. 1.Institut für Makromolekulare ChemieUniversität FreiburgFreiburg i. Br.FRG

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