Dong Jinfeng

Correlation of Critical Micelle Concentration of Sodium Alkyl Benzenesulfonates with Molecular Descriptors

The hydrophobic-hydrophilic segment geometries of 36 sodium alkyl benzenesulfonates were fully optimized and calculated by abinitio RHF/6-31G(d), quantum chemical data such as the charge density, the energy of molecular orbital and the dipole moment were obtained. Based on two topological descriptors and one quantum chemical descriptor, a significant quantitative structure-property relationship (QSPR) model for the critical micelle concentration (cmc) of sodium alkyl benzenesufonate surfactants was obtained by using the multiple linear regression technique. The good correlation coefficient ofR2 (0.980) and cross validation correlation coefficientRcv2 (0.974) indicate the excellent capability and stability of the regression equation developed. In addition, linear relationships between logarithm ofcmc and the dipole moment of surfactant hydrophobic hydrophilic segments for each homologous series have also been established with high correlation coefficient.

Metal Ions Induced Vesicle Formation of Single-Chained Hydrocarbon Surfactants with Coordinated Headgroups

The surfactant of N-dodecyliminodipropionate disodium salt has been synthesized, and structure has been well characterized. The properties in aqueous solution have been studied by potentiometric titration, surface tension, transmission electron microscopy (TEM) and ultra-violet (UV) spectra. It was found that N-dodecyliminodipropionate disodium could exist in four species (e. g. cation, zwitterion, monoanion, dianion) in aqueous solution depending on pH, and relative distribution of these ionic species as a function of pH was obtained. The critical micelle concentration (CMC), determined from the breakpoint of surface tension at different concentrations, is 4. 16×104 mol/L, and the surface tension at CMC is 30 mN/m. It was found that the self-aggregate structures in aqueous solution, transformed from micelles to vesicles after the Cu(II) added. The experimental results showed that coordination between the iminodipropionate group and Cu(II) resulted to vesicles formation.