Nuclear magnetic resonance investigation of the micellar properties of two-headed surfactant systems: the disodium 4-alkyl-3-sulfonatosuccinates. 2. The dynamics of the chains comprising the interior of two-headed surfactant micelles.
The dynamics of the carbons comprising the micelles of two members of the family of two-headed surfactants, the disodium 4-alkyl-3-sulfonatosuccinates, has been determined via the application of the two-step model to the 13C relaxation rates and the nuclear Overhauser enhancements (nOe's) at 200 MHz. The NMR relaxation times, determined from the inversion recovery method, increase steadily as we descend the chain from the headgroup region. The relaxation rate profiles and the order parameters have been calculated from the two-step model for the micellar sulfosuccinate aggregates. We note that the order parameter profile and the fast motion correlation time profile for these two-headed surfactants are distinctly different from those of a typical single-headed, single-tailed surfactant such as dodecyltrimethylammonium bromide, particularly in the headgroup region of the micelle. All these results are interpreted in terms of the effect of adding a second headgroup to a single-headed, single-tailed surfactant.
Doyle
Michael J
MJ
Department of Chemistry, St. Francis Xavier University, P.O. Box 5000, Antigonish, Nova Scotia, B2G 2W5, Canada.
Marangoni
D Gerrard
DG
D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008823:Micelles; D015394:Molecular Structure; D013386:Succinates / Q000737:chemistry*; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*
D002247:Carbon Isotopes; D008823:Micelles; D013386:Succinates; D013501:Surface-Active Agents