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

Different studies on the Aerosol AOT/water system have shown that the liquid crystal lamellar phase is strongly influenced by mechanical stresses. The effects of stirring or mechanical manipulations may relax within days or weeks. In this work pulsed field gradient spin echo-NMR water self-diffusion, D2O-NMR lineshape, and optical microscopy have been used to characterize the lamellar microstructures of the liquid crystal phase. In order to understand the effects of different mechanical stresses, water selfdiffusion has been interpreted using simulation procedures in which water molecules moved randomly in defective lamellar 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 domains in the relaxed and perturbed samples, respectively.