Elasticity of lyotropic chromonic liquid crystals probed by director reorientation in magnetic field

Oleg D Lavrentovich ,Shuang Zhou ,Yu A Nastishin ,M M Omelchenko ,L Tortora ,V G Nazarenko 2,O P Boiko 2,T Ostapenko 3,T Hu 3,C C Almasan 3,S N Sprunt 3,J T Gleeson 3

Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio, USA
Institute of Physical Optics, 23 Dragomanov str., Lviv, 79005, Ukraine
2Institute of Physics, prospect Nauky 46, Kiev-39, 03039, Ukraine
3Department of Physics, Kent State University, Kent, Ohio, USA

Using a magnetic Frederiks transition technique, we measured the temperature and concentration dependences of splay K1, twist K2, and bend K3 elastic constants for the lyotropic chromonic liquid crystal (LCLC) Sunset Yellow, formed through non-covalent reversible aggregation of organic molecules in water. K1 and K3 are comparable to each other and are an order of magnitude higher than K2. At higher concentrations and lower temperatures, K1 and the ratios K1/K3, K1/K2 increase, which is attributed to elongation of self-assembled LCLC aggregates, a feature not found in conventional thermotropic and lyotropic liquid crystals formed by covalently bound units of a fixed length.

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