Dear authors and readers!
We are pleased to inform that the journal Liquid Crystals and their Application is included in Web of Science (Emerging Sources Citation Index) and Scopus databases.
Zhidk. krist. ikh prakt. ispol'z. = Liq. Cryst. and their Appl., 2011, 4, 90—102.
Effects of Counter-Ion Specificity in Salt-Aqueous Solutions of Dodecylsulfates of Alcali Metals
A. Yu. Vlasov, K. R. Savchuk, A. A. Starikova, N. A. Smirnova
Author affiliations Saint-Petersburg State University, Chemistry Department
198504, St.Petersburg, Universitetskij pr., 26. E-mail: email@example.com
Abstract New experimental data are presented for aqueous solutions of sodium, potassium and cesium dodecylsulfates containing salt additives; the latter are chlorides having the same cations as the surfactants, the salt concentration spans 0 – 30 mmol/l. The information obtained includes the critical micelle concentrations, the aggregation numbers, concentrations of sphere-to-rod transitions, degrees of counter-ion binding, thermodynamic functions of aggregation (at 40oС and 45oС); data on the Krafft boundary. Counter-ion effects are analyzed from the standpoint of ions specificity towards water structuring in their micro-environment. In the proposed version of the quasi-chemical model the specific contribution to the Gibbs aggregation energy is described through parameters of the counter-ions adsorption on the micelle surface. The results of model estimations are in a satisfactory agreement with the ex-periment and conform to the concept of ions chaotropy or cosmotropy.
Keywords: ionic surfactants, micellization, effects of salt additives, counter-ion specificity, molecular-thermodynamic modeling