Flexoelectric effect in a bent-core liquid crystal measured by Dynamic Light Scattering

ORAL

Abstract

Flexoelectricity is a linear coupling between electric polarization and elastic flexure in liquid crystals [1]. Although typically quite weak in calamitic LCs, the flexoelectric effect has recently been shown, by direct (electromechanical) measurement of the flexure-induced polarization, to be enhanced by several orders of magnitude in certain bent-core nematic (BCN) liquid crystals [2]. We report here an application of dynamic light scattering to measure the flexoelectric coefficient ($e1 + e3$) of BCNs through coupling of polarization to elastic fluctuation modes of the optic axis. Our results agree in order of magnitude with the values obtained by the electromechanical method.\\~[1]~R.B. Meyer, \emph{Phys. Rev. Lett}. 22, 918 (1969).\\~[2]~J. Harden, B. Mbanga, N. Eber, K. Fodor-Csorba, S. Sprunt, J. T. Gleeson, A. Jakli, \emph{Phys. Rev. Lett}. 97, 157802 (2006).

*This work was financially supported by NSF Grant DMR- 0606160. We would like to thank J. Kim and W. Weissflog for synthesis of the bent-core material.

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Authors

  • Madhabi Majumdar

    • Kent State University

  • K. Neupane

    • Kent State University

  • J.T. Gleeson

    • Kent State University
    • Department of Physics, Kent State University, Kent OH

  • A. Jakli

    • Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University
    • Kent State University
    • Liquid Crystal Institute, Kent State University, Kent OH.

  • S. Sprunt

    • Kent State University
    • Department of Physics, Kent State University, Kent OH