THE APPLICATION OF A MIXED NONIONIC SURFACTANT THEORY TO TRANSITIONAL EMULSION PHASE INVERSION .2. THE RELATIONSHIP BETWEEN SURFACTANT PARTITIONING AND TRANSITIONAL INVERSION - A THERMODYNAMIC TREATMENT

Emulsion phase inversion in nonionic-surfactant-oil-water systems (nSOW) is directly related to the system’s phase behavior. A transitional inversion occurs when the surfactant’s affinity for oil and water is balanced and the system is 3 phase. The surfactant partitioning model, derived in part 1, is applied to transitional inversion in a number of different nSOW systems at a number of different temperatures. The surfactant partitioning results are used to show how nSOW phase behaviour and emulsion types can be related to thermodynamic parameters. It is further shown that transitional inversion points in nSOW systems at different temperatures are dependent on specific values of ΩH and ΩS, the enthalpy and entropy of phase transfer of the surfactant from bulk to interface respectively; these values depend on the surfactant type. The relationship between the ethyleneoxide chain length of interfacial surfactant and the phase inversion temperature is discussed also. © 1994 by Academic Press, Inc.