A NEW NMR-BASED TECHNIQUE FOR THE STUDY O F SELF-DIFFUSION

A method is proposed for the measurement of self-diffusion coefficient s in condensed media. To this end, a substance (or a mixture of substa nces) is brought into contract with the same substance (mixture), diff ering by the isotope composition, directly in the ampule of an NMR spe ctrometer or NMR relaxometer. Then the integral intensity of the NMR s ignal, or the maximum amplitude of the signal of free precession, is m easured in both parts of the ampule, and the diffusion-induced time va riations of the signal are monitored. Using this method, the self-diff usion coefficients were determined in an H2O-D2O mixture, in a mixture of light and heavy sulfolane in the plastic phase, and in polyurethan e-dioxane system. The self-diffusion coefficients measured by this tec hnique agree well with the values obtained by other methods.