Nanostructures of Nematic Materials of Laterally Branched Molecules

Authors

  • Randall Breckon,

    1. Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242 (USA), Fax: (+1) 330 672 22791
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  • Saonti Chakraborty,

    1. Department of Physics, Kent State University, Kent, OH 44242 (USA)
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  • Cuiyu Zhang,

    1. Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (USA, Fax: (+1) 330 672 4886
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  • Nicholas Diorio,

    1. Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (USA, Fax: (+1) 330 672 4886
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  • Prof. James T. Gleeson,

    1. Department of Physics, Kent State University, Kent, OH 44242 (USA)
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  • Prof. Samuel Sprunt,

    1. Department of Physics, Kent State University, Kent, OH 44242 (USA)
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  • Prof. Robert J. Twieg,

    Corresponding author
    1. Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242 (USA), Fax: (+1) 330 672 22791
    • Robert J. Twieg, Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242 (USA), Fax: (+1) 330 672 22791

      Antal Jákli, Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (USA, Fax: (+1) 330 672 4886

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  • Prof. Antal Jákli

    Corresponding author
    1. Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (USA, Fax: (+1) 330 672 4886
    • Robert J. Twieg, Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242 (USA), Fax: (+1) 330 672 22791

      Antal Jákli, Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242 (USA, Fax: (+1) 330 672 4886

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Abstract

The synthesis and small-angle X-ray scattering (SAXS) characterization is reported for 20 laterally branched mesogenic molecules, which are derived from the common rod-shaped 2,5-bis([4-(octyloxy)phenyl]carbonyloxy) benzoic acid unit. These compounds have a varying degree of flexibility, in that their lateral branch is formed upon conversion of the acid to either an ester or an amide, and most laterally branched molecules exhibit relatively wide nematic liquid-crystal phases with a direct nematic-to-crystal transition at lower temperatures. SAXS studies reveal the presence of smectic-like nanostructures (clusters) with short-range order in the nematic phase, with characteristic correlation lengths from 3 to over 10 nm. The smectic layers that are contained in these clusters are tilted with respect to the nematic director by angles ranging from 0° (i.e. untilted) to 55°. In some compounds, the intensity of the SAXS peak corresponding to the smectic layer spacing depends strongly on temperature. The main features of the nanostructures can be understood based on the molecular structure; therefore, guiding future synthetic work towards more precisely controlled and technologically useful nanostructures in nematics.

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