Guo Hongtao

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.