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.

*The work was supporeted by NSF grants DMR 1104850 and 11212878.

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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