General patterns of the phase behavior of mixtures of water, nonpolar solvents, amphiphiles, and electrolytes. 2

Abstract

In part 1 of this series (ref 1) we presented a qualitative thermodynamic description of the phase behavior of quaternary mixtures of water, nonpolar solvents, nonionic amphiphiles, and salts. The phase behavior of such mixtures follows general patterns that are essentially determined by the phase diagrams of the corresponding binary and ternary mixtures. In this paper (part 2) the nonionic amphiphiles are replaced by ionic amphiphiles. The general patterns of these mixtures, in particular the phase sequence with rising temperature, are inverse to those with nonionic amphiphiles? It is shown that this inverse behavior originates from the difference between the phase diagrams of binary H20-nonionic amphiphile and those of H20-ionic amphiphile mixtures.

Ionic Liquids in Microemulsions—A Concept To Extend the Conventional Thermal Stability Range of Microemulsions

“…96,97,98 This led to a better understanding of the phase behavior of C i E j surfactants, oil and water. Kahlweit et al 98 presented the temperature dependent phase diagram by vertically stacking the Gibbs triangles into a prism, with temperature on the vertical ordinate.…”

Nonaqueous Microemulsions Containing Ionic Liquids – Properties and Applications

“…The phase diagram, where the mass fraction of surfactant is shown as a function of temperature, takes the shape of a fish. These so-called fish cuts are the most often used twodimensional phase diagrams concerning microemulsions with non-ionic surfactants and have been studied systematically for aqueous microemulsions by Kahlweit et al (Kahlweit et al, 1988;Kahlweit et al, 1989). Atkin and Warr presented fish-cuts obtained for an equal ratio of water to oil for surfactants with increasing amphiphilicity (C 8 E 2 , C 12 E 3 , C 14 E 4 ).…”

Phase Behavior of Ionic Microemulsions

“…For high surface potentials this simplifies to rco-ion 2K I Csalt (13) (14) This means that in a flat double layer with high surface potential (say wo>>100 mV) the negative adsorption of coions is equal to the amount of co-ions in a layer with a thickness of twice the Debye length.…”