DIFFRACTION-LIKE EFFECTS OBSERVED IN THE PGSE EXPERIMENT WHEN APPLIEDTO A HIGHLY CONCENTRATED WATER OIL EMULSION/

The NMR pulsed gradient spin echo (PGSE) self-diffusion technique is a pplied to a system with permeable barriers. The system is a highly con centrated emulsion consisting of 97% water, and its internal structure is one of closely packed water droplets which are separated by thin o il films. These oil films are permeable to water, and the emulsion can therefore be considered as belonging to the general class of porous s ystems. Recently, Callaghan and co-workers showed both theoretically a nd experimentally that under certain conditions one may actually detec t diffraction-like effects when the ROSE experiment is applied to poro us systems. We report here for the first time such diffraction-like ef fects in an emulsion system, which were observed when examining the wa ter diffusion in the emulsion system mentioned above with the PGSE exp eriment. From the experiment the mean droplet size may be determined.