In this paper we introduce a model for the oil-water interfacial tension as a function of surfactant affinity in the three-phase region, as captured by the hydrophilic-lipophilic deviation (<i>HLD</i>), which relies on film bending energy arguments and empirical relationships for the microscopic curvatures. Following a similar approach, we present a model for the characteristic length scale. After an appropriate normalization, the interfacial tension is related to the characteristic length scale using a simple expression. Finally, we introduce models for the oil-microemulsion and microemulsion-water interfacial tensions using phase boundary condition arguments, which are extended to account for compositional changes using the appropriate limits. All models are compared against experimental data to demonstrate their validity, and for the data examined the the results give excellent fits.  The approach has the potential to predict two- and three-phase interfacial tension for changes in HLD input parameters, such as T, P, and overall composition.

Microemulsion interfacial tension and characteristic length scale model using a microscopic curvature approach and the HLD concept

253rd National Meeting (2017)

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