NMR Relaxation in Isotropic Surfactant Systems. A 2H, 13C, and 14N NMR Study of the Micellar (L1) and Cubic (I1) Phases in the Dodecyltrimethylammonium Chloride/Water System

Article abstract of DOI:10.1021/j100263a024

A 2H, 13C, 14N NMR spin relaxation study of micellar solutions and cubic liquid-crystalline phases formed in the two-component system dodecyltrimethylammonium chloride (DOTAC)¹/water is presented.In particular, based on multifield 2H NMR relaxation data, covering the frequency range 1.8-55.2 MHz, it is concluded that the NMR spin relaxation in ordinary micelles is determined by the fast local motion (trans-gauche isomerization) of the CD2 segment of the hydrocarbon chains of the monomers and the rotational tumbling of the micelles and diffusion of monomers over the (curved) micellar surface.There is no need to invoke other motions to explain the spin relaxation over a wide frequency range for he micellar case.For the cubic phase at high water content, the relaxation data are interpreted in favor of a novel structure, recently presented for this phase.The data also indicate that the interior or the amphiphilic aggregates is liquidlike and that the orientational order imposed by the hydrophobic-hydrophylic interface depends only weakly on the geometry of aggregates.

Full text of DOI:10.1021/j100263a024

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Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.