Journal ArticleDOI
Nematic phases of bent-core mesogens
Reads0
Chats0
TLDR
In this article, a temperature dependent stepwise transition from cybotactic nematic phases to different types of non-polar and tilted smectic phases (SmC(I) and SmC(II)) is observed with a mesophase composed of elongated, but not yet fused cybactic clusters (CybC) as an intermediate state of this transition.Abstract:
Bent-core mesogens derived from 4-cyanoresorcinol with terminal alkyl chains have been synthesized and investigated by polarizing microscopy, XRD and electro-optical methods. Short chain compounds have exclusively nematic phases which can be cooled to ambient temperature. These nematic phases are similar to ordinary nematic phases with only nearest neighbour correlation (N) whereas long chain compounds form SmC-type cybotactic clusters and these cybotactic nematic phases (NcybC) can be regarded as strongly fragmented SmC phases. The chain length dependent as well as temperature dependent structural transition from N to NcybC is continuous and associated with a change of the position and intensity of the small angle scattering in the XRD patterns. Moreover, a temperature dependent stepwise transition from cybotactic nematic phases to different types of non-polar and tilted smectic phases (SmC(I) and SmC(II)) is observed with a mesophase composed of elongated, but not yet fused cybotactic clusters (CybC) as an intermediate state of this transition. This improves the understanding of the nature and special properties of the nematic phases formed by bent-core molecules as well as their transition to smectic phases and it paves the way to new materials with spontaneous or field-induced biaxial nematic phases at ambient temperatures.read more
Citations
More filters
Journal ArticleDOI
Understanding the distinctive elastic constants in an oxadiazole bent-core nematic liquid crystal
Sarabjot Kaur,J. Addis,Cristina Greco,Alberta Ferrarini,Verena Görtz,John W. Goodby,Helen F. Gleeson +6 more
TL;DR: Calculated elastic constants via molecular-field theory and atomistic modeling are in excellent qualitative as well as good quantitative agreement with the measurements across the temperature range, offering a deeper understanding of the elasticity in bent-core nematic materials than has been, hitherto, available.
Journal ArticleDOI
Entwicklung struktureller Komplexität durch Selbstorganisation in flüssigkristallinen Systemen
Book ChapterDOI
Applications of Liquid Crystalline Elastomers
TL;DR: In this paper, the authors focus on the recent developments in the field of liquid crystalline elastomers (LCEs) that bring these materials closer to the world of real applications, concentrating on their actuation properties.
Journal ArticleDOI
Short-Range Smectic Order in Bent-Core Nematic Liquid Crystals
Seung Ho Hong,Rafael Verduzco,Jarrod Williams,Robert J. Twieg,Elaine DiMasi,Ron Pindak,Antal Jakli,James T. Gleeson,Samuel Sprunt +8 more
TL;DR: In this paper, small angle X-ray diffraction from the uniaxial nematic phase of certain bent-core liquid crystals is shown to be consistent with the presence of molecular clusters possessing short-range tilted smectic (smectic-C) order.
Journal ArticleDOI
A Molecular Theory of the Nematic-Nematic Phase Transitions in Mesogenic Dimers
TL;DR: In this paper, a simplified molecular model of mesogenic dimers consisting of two identical uniaxial mesogenic cores separated by a fixed-length spacer was presented, and allowed to assume only two, statistically equivalent, conformations which are non-planar and of opposite handedness.
References
More filters
Journal ArticleDOI
Simple Method for the Esterification of Carboxylic Acids
B. Neises,Wolfgang Steglich +1 more
Journal ArticleDOI
Bent-core liquid crystals: polar order, superstructural chirality and spontaneous desymmetrisation in soft matter systems
TL;DR: An overview on the recent developments in the field of liquid crystalline bent-core molecules (so-called banana liquid crystals) is given in this article, dealing with general aspects of the systematisation of the mesophases, development of polar order and chirality in this class of LC systems and explaining some general structure-property relationships.
Journal ArticleDOI
Bent-Core Liquid Crystals: Their Mysterious and Attractive World
Hideo Takezoe,Yoichi Takanishi +1 more
TL;DR: In this article, structural and properties of liquid crystalline phases formed by bent-core molecules are reviewed and the most attractive properties of this new class of liquid crystals are in polarity and chirality, despite being formed from achiral molecules.
Journal ArticleDOI
Thermotropic biaxial nematic liquid crystals.
TL;DR: Polarized microscopy and conoscopy indicate that liquid crystal mesogens based on a nonlinear oxadiazole unit that exhibit nematic phases near 200 degrees C are biaxial nematics, and unambiguous and quantitative evidence for biaXiality is achieved using 2H NMR spectroscopy.
Related Papers (5)
Bent-Core Liquid Crystals: Their Mysterious and Attractive World
Hideo Takezoe,Yoichi Takanishi +1 more