A phase-rule study of multiple-phase formation in a model emulsion system containing water, n-octanol, n-dodecane and/a non-ionic surface-active agent at 10 and 25°

Abstract

A four-component emulsion system containing the non-ionic surfactant C8H17 (O·CH2·CH2)6OH has been investigated, particularly in regions in which liquid crystal or more than two condensed phases are formed. Liquid crystal does not exist in the binary surfactant-water system at 25° but extensive regions form when the organic liquids octanol and dodecane are present, although these are not joined to the main two-liquid regions of the emulsion system. The surfactant is almost completely dissolved in the aqueous phase in water-dodecane mixtures but when substantial amounts of octanol are also present the partition coefficient is reversed in favour of the organic phase. At certain intermediate compositions three liquid phases are present. The significance of these results to the system as an emulsion are briefly discussed.