Development of Polar Order in the Liquid Crystal Phases of a 4‐Cyanoresorcinol‐Based Bent‐Core Mesogen with Fluorinated Azobenzene Wings |
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| Authors: | Dr Mohamed Alaasar Dr Marko Prehm Dr Maria‐Gabriela Tamba Dr Nerea Sebastián Dr Alexey Eremin Prof Dr Carsten Tschierske |
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| Affiliation: | 1. Institute of Chemistry, Organic Chemistry, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany;2. Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt;3. Institute for Experimental Physics, Otto-von-Guericke University Magdeburg, Magdeburg, Germany |
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| Abstract: | A bent‐core mesogen consisting of a 4‐cyanoresorcinol unit as the central core and laterally fluorinated azobenzene wings forms four different smectic LC phase structures in the sequence SmA–SmCs–SmCsPAR–M, all involving polar SmCsPS domains with growing coherence length of tilt and polar order on decreasing temperature. The SmA phase is a cluster‐type de Vries phase with randomized tilt and polar direction; in the paraelectric SmCs phase the tilt becomes uniform, although polar order is still short‐range. Increasing polar correlation leads to a new tilted and randomized polar smectic phase with antipolar correlation between the domains (SmCsPAR) which then transforms into a viscous polar mesophase M. As another interesting feature, spontaneous symmetry breaking by formation of a conglomerate of chiral domains is observed in the non‐polar paraelectric SmCs phase. |
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| Keywords: | azobenzene bent-core liquid crystals de Vries phase ferroelectricity mirror symmetry breaking |
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