CHARACTERIZATION OF THE LAMELLAR PHASE AEROSOL OT WATER-SYSTEM BY NMRDIFFUSION MEASUREMENTS

Different studies on the Aerosol AOT/water system have shown that the liquid crystal lamellar phase is strongly influenced by mechanical str esses. The effects of stirring or mechanical manipulations may relax w ithin days or weeks. In this work pulsed field gradient spin echo-NMR water self-diffusion, D2O-NMR lineshape, and optical microscopy have b een used to characterize the lamellar microstructures of the liquid cr ystal phase. In order to understand the effects of different mechanica l stresses, water selfdiffusion has been interpreted using simulation procedures in which water molecules moved randomly in defective lamell ar aggregates with a variable macroscopic time scale. Such a procedure gives values of about 50 and 17 mu m for the size of the lamellar dom ains in the relaxed and perturbed samples, respectively.