DISTRIBUTION EQUILIBRIA IN A MICELLAR SOLUTION SYSTEM

Various mixtures containing hydrocarbon, alkyl-aryl sulfonate, isopropyl alcohol, water, and sodium sulfate are found to give two equilibrium phases. The bottom phase is one of aqueous electrolyte with some dissolved alcohol, and the top phase is a clear micellar solution (microemulsion). The existence of the two-phase equilibrium allows the determination of the distribution ratios for water, electrolyte, and alcohol, and thus some insight into the thermodynamics of micellar solutions. The results further are applied to a previously proposed model for micellar emulsions which predicts how their water and electrolyte content should vary with the equilibrium external electrolyte concentration. Reasonable agreement is obtained and the model then provides estimated micellar radii which are in the range of the values given by independent approaches. © 1969.