FT PGSE NMR INVESTIGATION OF THE SUPRAMOLECULAR STRUCTURE OF A DILUTE GEL PHASE

The self-diffusion coefficients measured from Fourier tranform pulsed gradient spin-echo NMR (FT PGSE NMR) are used to investigate the dynamic structure of the dilute cetyl alcohol (CA)-sodium lauryl sulfate (SLS)-water gel phase. The effects of composition, sonication, and aging are investigated to provide a model of the gel macrostructure. The gel consists of a dispersion of irregularly shaped aggregates and swollen bilayer-like structures, which upon cooling form an emulsion of CA, stabilized by SLS, below the alpha-liquid transition temperature of the alcohol. The structural changes are monitored upon the addition of small increments of an oil phase to a dilute gel to investigate the emulsification mechanism. Although the dynamic interfacial diffusional processes cannot be measured during emulsification, a preliminary model for the mechanism of spontaneous emulsification in the gel phase is presented. © 1990.