Indication of a Twist-Grain-Boundary-Twist-Bend Phase of flexible bent-shape chiral dimers.

ORAL

Abstract

Flexible bent-core oligomers with odd-numbered methylene spacers exhibit a “twist-bend” nematic (NTB) phase characterized by a nanoscale heliconical pitch. We designed mixtures of achiral dimers, which exhibit the NTB phase, with a chiral additive. By differential scanning calorimetry, resonant soft X-ray scattering, polarized optical microscopy, and induced circular dichroism studies on condensed phases of these mixtures, we find, while in the nematic phase the micron-scale pitch of the additive-induced helical structure decreases with increasing additive concentration, in the N phase both the micron-scale and the nanoscale pitch of the ambidextrous spontaneous heliconical structure increase. At chiral additive concentrations above ~2% by weight, a new phase appears between the N* and NTB* phases, which we propose to be analogous to the twist-grain-boundary (TGB) phase of chiral smectics; we designate this new phase by TGBTB.

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Presenters

  • Matthew Murachver

    Chemical Physics Interdisciplinary Program, Kent State University

Authors

  • Matthew Murachver

    Chemical Physics Interdisciplinary Program, Kent State University

  • Ahlam Nemati

    Chemical Physics Interdisciplinary Program, Kent State University, Advanced Materials & Liquid Crystal Institute, Kent State University

  • Carson Bullock

    Department of Physics, College of Wooster

  • Zachary Sabata

    Department of Physics, Unversity of Nebraska, Omaha

  • Haumed Rahmani

    Chemical Physics Interdisciplinary Program, Kent State University

  • Tetiana Vorobiova

    Chemical Physics Interdisciplinary Program, Kent State University

  • Miroslaw Salamonczyk

    Faculty of Chemistry, University of Warsaw, Advanced Light Source, Lawrence Berkeley National Laboratory

  • Alain Izadnegahdar

    Advanced Precision Systems

  • Seyyed Salili

    Department of Physics & Astronomy, University of Pennsylvania

  • Victoria Norman

    Advanced Light Source, Lawrence Berkeley National Laboratory

  • Chenhui Zhu

    Advanced Light Source, Lawrence Berkeley National Laboratory

  • Torsten Hegmann

    Chemical Physics Interdisciplinary Program, Kent State University, Advanced Materials & Liquid Crystal Institute, Kent State University

  • Samuel N Sprunt

    Department of Physics, Kent State University

  • James Gleeson

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

  • Antal Istvan Jakli

    Liquid Crystal Institute, Kent State University, Department of Physics and Advanced Materials Liquid Crystal Institute, Kent State University, Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH USA, Chemical Physics Interdisciplinary Program, Kent State University, Advanced Materials & Liquid Crystal Institute, Kent State University, Kent State University, Department of Physics, Kent State University,Kent, OH 44240, USA