Thermodynamic analysis of the dynamic structure of micellar solutions of sodium alkyl sulfates
Y. A. Mirgorod
Keywords: sodium alkylsulfates, micelle, thermodynamic cycles, hydrophobic interaction, bistable structure
Pages: 920-925
Abstract
The results of previous studies of the increments ΔG0CH2, ΔH0CH2, TΔS0CH2 and in hydrocarbon solution processes in water, evaporation, hydration, and transfer from vapor and water to surfactant micelles are summarized. The corresponding thermodynamic cycles were constructed. A micelle was shown to be a bistable structure formed by the contact and water-separated hydrophobic interactions of the alkyl groups of surfactants. The fraction in ΔG0CH2M is -2.3 kJ⋅mol-1 for the contact associate and -0.7 kJ⋅mol-1 for the hydrated one. Water is involved in the hydrophobic interaction of each associate. In a dualist micelle, however, ΔG0CH2 = -3.0 kJ⋅mol-1 equals that of the dispersion interaction after condensation from vapor. The dual nature of the dynamic properties of micelles is discussed.
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