Tuesday, November 6, 2007
335aq

Coupling Between Diffusion And Orientation Relaxation In A Cromolyn Aqueous Solution

Kirt Linegar1, Adedayo Adeniran1, Andrei F. Kostko2, and Mikhail A. Anisimov1. (1) University of Maryland, Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, (2) Department of Chemical Engineering, Virginia Commonwealth University, Richmond, VA 22284

The isotropic-to-nematic pretransitional fluctuations of the aqueous solution of disodium cromoglycate (cromolyn) have been studied by dynamic light scattering. Cromolyn is a representative of lyotropic chromonic liquid crystals with building units being elongated rods formed by aggregates of disc-like molecules. We have obtained the relaxation time of the orientational order-parameter fluctuations and the diffusion relaxation time as functions of temperature and wave numbers of light scattering. A coupling between the diffusion and the orientation relaxation is revealed through the dependence of the observed effective dynamic modes on the wave number.