Solvation thermodynamic parameters for sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES) surfactants in aqueous and alcoholic-aqueous solvents

Abstract

Conductivity of sodium dodecyl sulfate (SDS) and sodium lauryl ether sulfate (SLES) surfactants in aqueous and in alcoholic-aqueous mixed solvents (methanol, ethanol, and glycerol) with different mole fractions of alcohols has been measured experimentally at different temperatures (298.15, 303.15, 308.15 and 313.15 K). Surface tension was also measured experimentally for SDS and SLES in aqueous solution at 298.15 K. Critical micelle concentration (CMC) of both SDS and SLES was determined from the measured conductivity and surface tension data. The CMC was found to increase as the temperature and alcohol mole fraction increased in all solvents used. Depending on the conductivity data, the association constant (K a ) of both SDS and SLES was also determined applying Shedlowsky conductance equation. The thermodynamic parameters (ΔG˚, ΔH˚, and ΔS˚) of the micellization and association processes were evaluated from the temperature dependence of micellization and association constants. The results indicate that the association constant of both SDS and SLES decrease as the temperature and alcohol mole fraction increased in all solvents used. Also it was found that CMC and K a of both SDS and SLES increase in the order: methanol > ethanol > glycerol. The association process was found to be spontaneous one. The density and refractive index of both SDS and SLES in aqueous and in alcoholicaqueous mixed solvents (methanol, ethanol, and glycerol) with different mole fractions of alcohols, has been measured experimentally at 298.15 K. Depending on the density data, the molar volume of the two surfactants was determined and discussed. Also depending on the refractive index data, the molar refraction and the polarizability of both SDS and SLES was calculated and discussed. A computer programs were used for all calculations.

Structural Transitions of Anionic, Cationic, and Nonionic Surfactant Solutions Confined between Amorphous SiO2 Slabs: Molecular Dynamics Simulations

“…The surface tension is obtained by the integral of the difference between the diagonal components of the pressure tensor γ = − b z ( P xx + P yy – 2 P zz )/4 where b z is the length of the simulation box along the z axis, and P xx , P yy , and P zz are the principal components of the pressure tensor . As shown in Figure S1, the surface tensions obtained from liquid/vapor interface simulations are in good agreement with experimental results. , Experimental data for other systems were not reported in the literature to the best of our knowledge. Therefore, comparison of simulated results with experiments is not possible.…”

“…28 As shown in Figure S1, the surface tensions obtained from liquid/vapor interface simulations are in good agreement with experimental results. 29,30 Experimental data for other systems were not reported in the literature to the best of our knowledge. Therefore, comparison of simulated results with experiments is not possible.…”

Chitosan/Sodium Dodecyl Sulfate Complexes for Microencapsulation of Vitamin E and Its Release Profile—Understanding the Effect of Anionic Surfactant

“…In a related study [41], the addition of ethanol to the acceptor medium, in order to enhance the solubility of the released substance in the acceptor medium was recommended. Moreover, in a study by Farid et al [42], it has been shown that in ethanol/water mixtures the critical micellar concentration of SDS increases with the increasing ethanol concentration. Therefore, the use of ethanol at a concentration of 80% as an acceptor medium precluded the potential risk for solubilization of vitamin E in the acceptor medium, which could affect the detected amount of vitamin E released.…”

Micellization and Solvation Properties of Newly Synthesized Imidazolium- and Aminium-Based Surfactants

“…The variation of the CMC with chemical and physical parameters provides a perfect view for the nature of the surfactant self-association. Methods for CMC determination include conductivity, viscosity, surface tension, ion activity, dye incorporation, gel filtration spectrophotometrically, counterion magnetic resonance, and refractive index measurements. − Solvation of different cationic surfactants in different solvents was investigated before, − where CMC was measured with different methods. Also, density, refractive index, and UV spectra measurements of solutions are expected to shed some light on the solute–solvent interactions and configuration of their mixtures. − Other thermodynamic properties including molal volume, ionic association, and polarizability were investigated for ionic liquids, , especially for imidazolium ionic liquid surfactants. − …”