Thermodynamics of micellization from heat-capacity measurements.

Differential scanning calorimetry (DSC), the most important technique for studying the thermodynamics of structural transitions of biological macromolecules, is seldom used in quantitative thermodynamic studies of surfactant micellization/demicellization. The reason for this could be ascribed to an insufficient understanding of the temperature dependence of the heat capacity of surfactant solutions (DSC data) in terms of thermodynamics, which leads to problems with the design of experiments and interpretation of the output signals. We address these issues by careful design of DSC experiments performed with solutions of ionic and nonionic surfactants at various surfactant concentrations, and individual and global mass-action model analysis of the obtained DSC data.

What affects the degree of micelle ionization: conductivity study of alkyltrimethylammonium chlorides.

The critical micelle concentration, cmc, and the degree of micelle ionization, β, of decyltrimethylammonium chloride (DeTAC), dodecyltrimethylammonium chloride (DTAC) and tetradecyltrimethylammonium chloride (TTAC) in water, 0.01 M, and 0.1 M NaCl solution were determined from the electrical conductivity data in the temperature range from 278.

Salicylate isomer-specific effect on the micellization of dodecyltrimethylammonium chloride: large effects from small changes.

Specific effects of the sodium salts of m- and p-hydroxybenzoates (m-HB and p-HB) on the aggregation process of dodecyltrimethylammonium chloride have been investigated by isothermal titration calorimetry, electrical conductivity, and (1)H NMR and compared with already reported data for the sodium salt of o-hydroxybenzoate (o-HB). For p-HB, it has been found that the aggregate is only formed by spherical micelles at all p-HB concentrations. On the other side, the situation is more complex for o-HB, where two distinct states of aggregation can be involved, depending on the concentration of o-HB.

Thermodynamic characterization of 3-[(3-cholamidopropyl)-dimethylammonium]-1-propanesulfonate (CHAPS) micellization using isothermal titration calorimetry: temperature, salt, and pH dependence.

A systematic investigation of the micellization process of a biocompatible zwitterionic surfactant 3-[(3-cholamidopropyl)-dimethylammonium]-1-propanesulfonate (CHAPS) has been carried out by isothermal titration calorimetry (ITC) at temperatures between 278.15 K and 328.15 K in water, aqueous NaCl (0.

Temperature and salt-induced micellization of dodecyltrimethylammonium chloride in aqueous solution: a thermodynamic study.

Thermodynamics of micelle formation of the cationic surfactant dodecyltrimethylammonium chloride (DTAC) in water and aqueous NaCl solutions were investigated. Isothermal titration calorimetry (ITC) has been used to study the effect of the added NaCl on the critical micelle concentration, cmc, and enthalpy of micellization, Delta(mic)H(o), between 278.15 and 318.