Effect of ionic additives on elasticity of lyotropic chromonic liquid crystal

ORAL

Abstract

Using a magnetic Frederiks transition technique, we determine how the splay $K_{1}$ and bend $K_{3}$ elastic constants of lyotropic chromonic liquid crystal Sunset Yellow (SSY) depend on concentration of ionic additives, sodium chloride (NaCl) and magnesium sulfate (MgSO$_{4}$). Both salts increase the ratio $K_{1}/K_{3}$, by mainly increasing $K_{1}$ (MgSO$_{4}$) or mainly decreasing $K_{3}$ (NaCl). The effects are attributed to the screening of electrostatic repulsions of chromonic molecules, which is expected to increase the contour length (thus increasing $K_{1}$) and to decrease the persistence length (thus decreasing $K_{3}$) of the chromonic aggregates in which the molecules are stacked face-to-face. As in salt-free SSY, the ratio $K_{1}/K_{3}$ increases when the temperature decreases.

–

Authors

  • Shuang Zhou

    Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242

  • Adam J. Cervenka

    Bates College, Lewiston, ME 04240

  • Y.P. Singh

    Kent State University, Department of Physics, Kent State University, Kent, Ohio 44242, Kent State University, USA

  • Luana T. Tortora

    Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242

  • C.C. Almasan

    Kent State University, Department of Physics, Kent State University, Kent, Ohio 44242, Kent State University, USA

  • Oleg D. Lavrentovich

    Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, 44240, OH, Kent State University, Liquid crystal institute and chemical physics interdisciplinary program, Kent state university, Kent, OH, USA, Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, Ohio 44242