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Updated: Jul 7, 2026

Self-assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives
Published on: February 7, 2017
Star-shaped oligobenzoates: non-conventional mesogens forming columnar helical mesophases
Matthias Lehmann1, Michael Jahr, Bertrand Donnio
1Institute of Chemistry, Chemnitz University of Technology, Strasse der Nationen 62, 09111 Chemnitz, Germany. matthias.lehmann@chemie.tu-chemnitz.de
Abstract:
Star-shaped mesogens with a phloroglucinol or a trimesic acid core and oligobenzoate arms with up to five repeating units have been synthesised. These non-conventional mesogens form various columnar mesophases over a broad temperature range. The liquid-crystal phases were characterised by optical microscopy, differential scanning calorimetry, X-ray diffraction, dilatometry and solid-state NMR spectroscopy. In addition to the high-temperature hexagonal columnar phases, the columnar self-assemblies undulate upon cooling and consequently form higher-ordered body-centred orthorhombic columnar 3D structures. A model of E-shaped folded conformers helically displaced along the columns is proposed. Helical preorganisation in the hexagonal phase precedes the transition to the low-temperature phases. Space filling and nano-segregation compete in the self-organisation process, thus aliphatic chains and the polar oligobenzoate scaffold are not perfectly separated in these star-shaped mesogens.
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