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 K2 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.
@article{arxiv.0807.2669,
title = {Elasticity and Viscosity of a Lyotropic Chromonic Nematic Studied with Dynamic Light Scattering},
author = {Yu. A. Nastishin and K. Neupane and A. R. Baldwin and O. D. Lavrentovich and S. Sprunt},
journal= {arXiv preprint arXiv:0807.2669},
year = {2008}
}