FT-IR and dielectric study of water/AOT liquid crystals

In order to explore the influence of microwave radiation on highly viscous microheterogeneous systems, the evolution of structural and dynamical prope rties of the water/sodium bis(2-ethylhexyl) sulfosuccinate (AOT) liquid cry stals as a function of the molar ratio R (R = [water]/[AOT]) has been inves tigated by FT-IR spectroscopy and time domain reflectometry. The study emph asises how the progressive hydration of the surfactant head groups is mainl y responsible for the structural and dynamical evolution of water/AOT liqui d crystals. In particular, it has been found that the state of water at low er R values is strongly perturbed, bulk-like water appears only at R > 23 a nd the water/AOT interface polarisation is controlled by the fast translati onal dynamics of sodium counterions and the slow orientational dynamics of the AOT ionic head groups. (C) 2000 Elsevier Science B.V. All rights reserv ed.