SELF-DIFFUSION OF WATER IN QUATERNARY SURFACTANT SYSTEMS

The self-diffusion coefficient of water in the quaternary surfactant s ystem tetradecyl dimethyl aminoxide (TDMAO)/tetradecyl trimethyl ammon ium bromide (TTABr)/hexanol (C6OH)/water is determined in dependence o n salinity and diffusion time. The effects of the shielding of the ele ctrostatic repulsion induced by addition of NaCl are reflected in the self-diffusion coefficient of extravesicular water. Results indicate t hat addition of NaCl first causes a deformation of the vesicles. Upon further increase in salinity, the apparent self-diffusion coefficient becomes dependent on diffusion time, which indicates a phase transform ation. Additional support for this conclusion is obtained from measure ments of the line width of the water signal by H-2-NMR in correspondin g TDMAO/TTMABr/C6OH/D2O samples.