Elasticity and Viscosity of a Lyotropic Chromonic Nematic Studied with Dynamic Light Scattering.

Oleg D. Lavrentovich ,Yuriy A. Nastishin ,Krishna Neupane 2,Alan R. Baldwin 2,Oleg D. Lavrentovich 3,Samuel Sprunt 2

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.


Full Document