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The alignment of lyotropic liquid crystals formed by hexadecyltrimethylammonium bromide (CTAB, where C stands for cetyl) with D2O was studied by the use of 2H NMR. At CTAB/D2O concentrations between 1.01 and 1.29 mol/kg, liquid crystal domains aligned in the magnetic field within a few hours. The dependence of the characteristic alignment time on concentration and temperature has been determined. At higher concentrations, no alignment took place due to the high viscosity of the system. At lower concentrations, the alignment could not be observed by 2H NMR. The addition of sodium salicylate (NaSal), at equal molar concentrations of CTAB and NaSal, changed the orientation of the micelles from parallel to the magnetic field to perpendicular to the field. Line-shape simulations were carried out to give estimates on the rate of exchange between free D2O molecules and those bounded to the micelles, as well as on the deuterium quadrupole splittings for D2O molecules bound to micelles. The dependence of the characteristic alignment time on the strength of magnetic field was also studied.

The N14 NMR spectra of solids are usually very broad due to the presence of large quadrupole coupling constants. However, even partial excitation of the whole spectrum can give valuable information. With magic angle spinning (MAS), the spectrum consists of a number of peaks, but normally the centerband cannot be readily distinguished from the spinning sidebands. Multiple-pulse methods of sideband elimination, such as TOSS and PASS, cannot be used for N14 because of its short spin–spin relaxation time. On the other hand, the sidebands can be eliminated by systematic data treatment. First, the signal-to-noise ratio (S/N) is enhanced by co-adding all the peaks in a MAS spectrum in a periodic way. Then, several spectra obtained at different spinning rates are added or multiplied together to identify the centerband. In the centerband region of the spectrum obtained from the addition method, the residual sidebands can be distinguished from the weak signals by the use of logical or digital filtering. Results obtained by using these methods to treat the spectra of two mixtures of KNO3, Pb(NO3)2, and NH4Cl are shown. The experimental requirements are not very stringent, the S/N ratio is good, and peaks covering a large range of chemical shifts can be readily observed with high-resolution.