Elasticity and Viscosity of a Lyotropic Chromonic Nematic Studied with Dynamic Light Scattering.
Oleg D. Lavrentovich
,Yuriy A. Nastishin
2,Alan R. Baldwin
2,Oleg D. Lavrentovich
Liquid Crystal Institute
Liquid Crystal Institute, Kent State University, POB 5190, Kent, OH, 44242 & Institute of Physical Optics, 23 Dragomanov str. Lviv 79005 Ukraine
2Department of Physics, Kent State University, Kent, OH, 44242
3Liquid Crystal Institute, Kent State University, POB 5190, Kent, OH, 44242 & Chemical Physics Interdisciplinary Program, Kent State University
Using dynamic light scattering, we measure for the first time the temperature-dependent elastic moduli and associated orientational viscosity coefficients of the nematic phase in a self-assembled lyotropic chromonic liquid crystal. The bend K3 and splay K1 moduli are an order of magnitude higher than the twist K constant. The ratio K3/K1 shows an anomalous increase with temperature; we attribute this to the shortening of the aggregates as temperature increases. The viscosity coefficients also show a significant anisotropy, as well as a strong temperature dependence; in particular, the bend viscosity is three orders of magnitude smaller than the splay and twist viscosities.