1H NMR Study of Mixed Micellization of Sodium Dodecyl Sulfate and Triton X-100

Mixed Micelles of Polyethylene Glycol (23) Lauryl Ether with Ionic Surfactants Studied by Proton 1D and 2D NMR

“…By the use of the 1D and 2D NMR techniques we have recently shown (17) that the α-methylene group of CTAB is located in the near vicinity of the phenoxy ring of the nonionic surfactant, Triton X-100 (TX-100), in their mixed micelles, and the end methyl group of CTAB is close to those of TX-100. Furthermore, the closely packed (coiled) hydrophilic polyethylene chains in the exterior part of the mixed micelles gradually extend with an increase in the CTAB component in the mixed solution, whereas the mixing of TX-100 with the anionic surfactant, SDS, does not show this effect (18). It is of interest to extend this finding with exchanging the phenyl group with an alkyl group and an increase in the length of the poly oxy-ethylene chain in the poly-oxyethylene glycol ether to examine the detailed microstructure of the mixed micelles formed.…”

NMR studies of surfactants

“…It is important to note that such effects are not directly distance-related, but rather reflect a dipole-like shielding effect that has an angular (3 cos 2 Ϫ 1), as well as a 1/r 3 distance dependence. Multidimensional, distance-sensitive NMR experiments like NOESY have also found use in this context (67)(68)(69).…”

Study on Micelle Formation of Bile Salt Using Nuclear Magnetic Resonance Spectroscopy

“…In general, the rotational and translational motions for amphiphile s molecules in the micelle are more restricted than those in monomer state, therefore, the T 1 of proton in the micellar interior is relative shorter than that in the surrounding solvent 25 . For example, the technique for T 1 measurement has been used to determine the motional freedom for surfactant in mixed micelles 26 or change of extent of the molecular motion in the micellar core by solubilization 27 . The relaxation time T 1 for the four bile salt species was measured as a function of bile salt concentration.…”

“…However, T 1 values could only be obtained for sharp peaks in the 1 H NMR spectra. In general, T 1 values for protons at both hydrophilic and hydrophobic sites drastically decrease upon micelles formation in aliphatic surfactant systems 26 , because proximal molecules limit the dynamic behavior of each molecule within the micelle. However, there is an uncommon example in which T 1 increases with concentration after micelle formation with including present study 28 .…”