Topic
Columnar phase
About: Columnar phase is a research topic. Over the lifetime, 1578 publications have been published within this topic receiving 51660 citations.
Papers published on a yearly basis
Papers
TL;DR: The columnar liquid crystals based on symmetric hairpin-shaped cholesterol tetramers bridged by rigid or hydrogen-bonding Schiff base spacers were prepared by reacting cholesterol dimer with phenylenediamines or dihydrazides in yields of 70-85% as mentioned in this paper.
Abstract: The novel columnar liquid crystals based on symmetric hairpin-shaped cholesterol tetramers bridged by rigid or hydrogen-bonding Schiff-base spacers were prepared by reacting cholesterol dimer with phenylenediamines or dihydrazides in yields of 70–85%. Structural characterisation of these new compounds had been achieved by infrared, nuclear magnetic resonance and mass spectrometry. Their mesomorphic properties were investigated by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. They exhibited good hexagonal columnar mesophase with three molecules in a disc of the columnar hexagonal state. This study implied that the symmetric cholesterol tetramers with rigid cores or hydrogen-bonding cores prefer to columnar mesophase.
16 citations
16 citations
TL;DR: In this article, the columnar mesomorphism and homeotropic alignment properties of hexaphenoxy-substituted phthalocyanine derivatives were investigated using polarizing optical microscopic observations, differential scanning calorimetry and temperature-dependent X-ray diffraction studies.
Abstract: We have synthesized novel hexaphenoxy-substituted phthalocyanine derivatives, 2-(12-hydroxydodecyloxy)-3-methoxy-9,10,16,17,23,24-hexakis(3,4-di-n-alkoxyphenoxy)phthalocyaninato copper(II) (abbreviated as Cn(OC12OH)PcCu: n = 10, 12, 14), and investigated their columnar mesomorphism and homeotropic alignment property. These hexaphenoxy-substituted Pc derivatives could be successfully isolated and purified from the mixture products by polarity difference. It was revealed by using polarizing optical microscopic observations, differential scanning calorimetry and temperature-dependent X-ray diffraction studies that each of the hexaphenoxy-substituted Pc derivatives has plural mesophases, and that the tetragonal columnar (Coltet) mesophase shows spontaneous perfect homeotropic alignment between two non-surface-treated glass plates without any defects and polydomain boundaries.
16 citations
TL;DR: In this paper, the molecular ordering and the dynamics of the isotropic and columnar liquid crystalline phase of hexapentoxytriphenylene have been studied by high resolution proton NMR, self-diffusion measurements and spin-lattice relaxation in the laboratory (T1) and the rotating frame (T 1ρ).
Abstract: The molecular ordering and the dynamics of the isotropic and the discotic columnar liquid crystalline phase of hexapentoxy‐triphenylene have been studied by high resolution proton NMR, self‐diffusion measurements and spin–lattice relaxation in the laboratory (T1) and the rotating frame (T1ρ). The onset of the columnar ordering is accompanied by the gradual appearance of a short ’’liquid crystalline’’ component in the proton free induction decay (FID) in addition to the long component characteristic of the isotropic phase. The proton T1 is frequency dependent in the isotropic and in the columnar phase. It changes discontinuously at the clearing point at low frequencies where as it is continuous at 270 MHz. An analysis of the possible relaxation mechanisms is presented.
16 citations
TL;DR: A homologous series of hexa-n-alkanoyloxy trithiatruxenes (2,3,7,8,12,13,13-hexa-nalkaneyloxybenzo]-trisbenzothiophenes (Cn HATXS) was prepared with n = 9 to n = 13 in order to study the influence of the substitution of the three methylenes of the truxene core by three sulphur atoms on the mesomorphic properties as discussed by the authors.
Abstract: A homologous series of hexa-n-alkanoyloxy trithiatruxenes (2,3,7,8,12,13-hexa-n-alkanoyloxybenzo-[1, 2-b : 3, 4-b': 5,6-b”]trisbenzothiophenes) (Cn HATXS) has been prepared with n = 9 to n = 13 in order to study the influence of the substitution of the three methylenes of the truxene core by three sulphur atoms on the mesomorphic properties. Phase transitions were studied by hot stage microscopy and DSC. This series shows another example of an inverted sequence (crystal-ND nematic-D columnar-isotropic) and a new polymorphism with a columnar phase between Dh and Drd phases.
16 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2024 | 9 |
| 2023 | 14 |
| 2022 | 14 |
| 2021 | 17 |
| 2020 | 19 |
| 2019 | 24 |