Non-symmetrical bent-shaped liquid crystals with five ester groups

Abstract

In this study a new series of bent-core liquid crystals based on laterally substituted 7-hydroxynaphthalene-2-carboxylic acid is presented. All compounds exhibit broken-layer type columnar phases. For CH₃ laterally substituted compounds with a longer chain we found a smectic A above a columnar phase on cooling from the isotropic phase. Additionally, for CH₃-substituted compounds with the longest chains (C₁₄H₂₉) two switchable columnar phases (B_1RevT) occurred below the SmA phase. Two columnar phases were also found for Cl-substituted homologues with the long chain C₁₂H₂₅ and C₁₄H₂₉. For the Cl-substituted materials we found significant lowering of transition temperatures and a very steady columnar phase in a broad temperature interval of up to 130 K.

Keywords:

• bent-shaped liquid crystals
• ester linkage orientation
• naphthalene
• mesomorphic properties

Acknowledgements

This work was supported by projects OC176 and MSM6046137301 (Ministry of Education, Youth and Sports of the Czech Republic) and by grant IAA100100911 (Grant Agency of AS CR) and grant No. 202/09/0047 from the Grant Agency of the Czech Republic. The X-ray diffraction measurements were completed at the Structural Research Laboratory, Chemistry Department, University of Warsaw, Poland, which has been established with financial support from European Regional Development Fund, project No: WKP 1/1.4.3./1/2004/72/72/165/2005/U.