A thermo-birefringence switchable columnar liquid crystalline compound

• Published in: Materials letters Vol. 307; p. 131055
• Main Authors: Masuda, Masaya, Kobayashi, Takuya, Kohri, Michinari, Kishikawa, Keiki
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2022; Elsevier BV
• Subjects: Birefringence; Birefringence inversion; Chemical synthesis; Columnar liquid crystal; Hydrogen bonding; Liquid crystals; Materials science; Microscopes; Optical materials; Optical microscopy; Optical switching; Phases; Polarized light; Thermo-optical switching; Ureas; Thermo-optical switching; Optical materials; Columnar liquid crystal; Birefringence inversion
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2021.131055

[Display omitted] •The columnar liquid crystal showed a change in birefringence with temperature.•A clear positive-to-negative birefringence switch occurred at the phase transition.•The change in birefringence is due to a change in the molecular conformation.•All the anisotropic texture disappears completely during the phase transition. In the field of columnar liquid crystals, a new type of thermo-optical switching material that shows a birefringence inversion without changing the columnar alignment by controlling the temperature was synthesized. The urea molecules generate one-dimensional linear molecular aggregates using urea-urea intermolecular hydrogen bonding and exhibit rectangular and hexagonal columnar phases. In polarized light optical microscopy, the texture perfectly disappears during the transition between the two columnar phases because it passes through the point where birefringence becomes zero. The inversion mechanism is explained by the conformational change of each molecule in the column. In this study, we propose a new switchable optical material in columnar liquid crystal phases.