Thermodynamics and Structure of Micelles in Aqueous Solutions of Sodium Decyl Sulfate in the Region of the Third Critical Micelle Concentration

• Published in: Russian Journal of Physical Chemistry A Vol. 93; no. 8; pp. 1471 - 1477
• Main Authors: Kuznetsov, V. S., Zherdev, V. P., Badelin, V. G., Zherdeva, V. V.
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.08.2019; Springer Nature B.V
• Subjects: Aqueous solutions; Chemistry; Chemistry and Materials Science; Gibbs free energy; Mathematical analysis; Micelles; Physical Chemistry; Physical Chemistry of Solutions; third critical micelle concentration; polymorphic transition; components of the Gibbs free energy of transition; aggregation numbers and structure of cylindrical and lamellar micelles
• ISSN: 0036-0244; 1531-863X
• DOI: 10.1134/S0036024419080156

Using data on heat capacity of sodium decyl sulfate solutions near the third critical micelle concentration, obtained earlier via high-precision scanning calorimetry, the temperature dependences are calculated for the thermodynamic functions of the corresponding micellar transition and the components of its Gibbs free energy. It is shown that the considered intermicellar transition, interpreted as the micellar shape transforming from cylindrical to lamellar as the concentration grows, occurs at an equilibrium molality of 0.33 and a temperature of 323 K. Correlations between the thermodynamic functions of the transition with structural changes in the micelles and the key micellar parameters are discussed.