scholarly journals Bicontinuous Cubic and Hexagonal Columnar Liquid Crystalline Ion-Conductors at Room Temperature in Ion-Doped Dendritic Amphiphiles

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 193
Author(s):  
Thi Huyen Do ◽  
Ho-Joong Kim ◽  
Manh Linh Nguyen ◽  
Byoung-Ki Cho
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Molecular Design ◽  
Three Dimensional ◽  
Impedance Analysis ◽  
Practical Applications ◽  
Alkyl Chains ◽  
Bicontinuous Cubic ◽  
Hexagonal Columnar ◽  
Ion Conductors

A bicontinuous cubic (Cubbi) liquid crystalline (LC) phase consisting of three dimensional (3D) conducting networks is a promising structural platform for ion-conductors. For practical applications using this fascinating LC structure, it is necessary to suppress crystallization at room temperature (RT). Herein, we report the Cubbi structure at RT and the morphology–dependent conduction behavior in ionic samples of a non-crystallizable dendritic amphiphile. In the molecular design, branched alkyl chains were used as an ionophobic part instead of crystallizable linear alkyl chains. Two ionic samples with Cubbi and hexagonal columnar (Colhex) LC phases at RT were prepared by adding different amounts of lithium salt to the amphiphile. Impedance analysis demonstrated that the Cubbi phase contributed to the faster ion-conduction to a larger extent than the Colhex phase due to the 3D ionic networks of the Cubbi phase. In addition, the temperature–dependent impedance and electric modulus data provided information regarding the phase transition from microphase-separated phase to molecularly mixed liquid phase.

scholarly journals X-Ray Diffraction Studies on Alicyclic Saturated Discotic Liquid Crystals

1987 ◽  
Vol 42 (6) ◽  
pp. 631-635 ◽  
Author(s):  
H. W. Neuling ◽  
H. Stegemeyer ◽  
K. Praefcke ◽  
B. Kohne
Keyword(s):  
Liquid Crystalline ◽  
Optical Observations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkyl Chains ◽  
New Class ◽  
X Ray Scattering ◽  
Oriented Samples ◽  
Hexagonal Columnar

The discotic liquid crystalline phase of a new class of disc-like molecules (hexa-O-alkanoylscyllo- inositoles) is studied by small angle X-ray scattering, DSC and optical observations. Comparison of these three methods allows the determination of the structural arrangement. X-ray film exposures of oriented samples clearly demonstrate the hexagonal columnar ordered type of mesophases. A simple model calculation shows that the alkyl chains of neighbouring columns interpenetrate each other to a small extent.

scholarly journals Self-template–assisted micro-phase segregation in blended liquid-crystalline block copolymers films toward three-dimensional structures

2020 ◽  
Vol 117 (35) ◽  
pp. 21070-21078
Author(s):  
Yusuke Hibi ◽  
Yuki Oguchi ◽  
Yuta Shimizu ◽  
Kayoko Hashimoto ◽  
Katsuya Kondo ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Three Dimensional ◽  
Phase Segregation ◽  
Material Design ◽  
The Other ◽  
Cooling Process ◽  
Water Separation ◽  
Practical Applications ◽  
Out Of Plane ◽  
Fundamental Research

In-plane mesopatterns derived from block-copolymer (BCP) micro-phase segregation in thin films have attracted much interest in practical applications as well as fundamental research programs. However, phase segregation along the film-normal direction has been less studied. Here, we describe a strategy to concurrently, yet independently, control in-plane micro-phase and out-of-plane macro-phase segregation in multiblended films composed of liquid-crystalline BCPs (LCBCPs), affording spontaneously layered three-dimensional (3D) mesostructures. This strategy relies on sequential liquid crystallization during the cooling process in thermal annealing as follows. The constituent LCBCP with the highest isotropic-transition temperature (Tiso) first liquid-crystallizes and segregates from the other LCBCP mixture remaining in isotropic states to form a noncontaminated layer at the top surface. This preformed LCBCP layer preserves its inherent in-plane pattern and acts as a template guiding the subsequent micro-phase segregations of the other low-TisoLCBCPs underneath. This self-template–assisted micro-phase segregation (STAMPS) readily provides 3D mesostructures, the potential toward rational material design of which is also demonstrated in water-separation applications.

scholarly journals Luminescence Tuning of Fluorinated Bistolanes via Electronic or Aggregated-Structure Control

2019 ◽  
Vol 9 (9) ◽  
pp. 1905 ◽  
Author(s):  
Masato Morita ◽  
Shigeyuki Yamada ◽  
Tomohiro Agou ◽  
Toshio Kubota ◽  
Tsutomu Konno
Keyword(s):  
Phase Transition ◽  
Liquid Crystalline ◽  
Molecular Design ◽  
Thermal Conditions ◽  
Light Emitting ◽  
Practical Applications ◽  
Precise Control ◽  
Structure Control ◽  
Wide Range ◽  
External Stimuli

Organic luminescent materials have a wide range of practical applications, but the understanding of the relationship between molecular structure and luminescent behavior is lacking. Herein, we synthesized fluorinated bistolanes with an electron-donating alkoxy substituent at one terminal and an electron-withdrawing substituent at the other to realize systematic control of the electron-density distribution. Evaluation of the phase transition behavior revealed that most of the fluorinated bistolanes showed liquid-crystalline (LC) behavior, with the phase transition temperature depending on the terminal substituents. Additionally, the fluorinated luminophores displayed intense photoluminescence (PL) in solution and in their crystal phases. Remarkably, the PL color shifted dramatically depending on the dipole moment (μ||) along the long molecular axis; thus, PL tuning can be achieved through electronic modulation by precise control of the μ|| of the luminophore. Interestingly, in the LC phases under thermal conditions, the maximum PL band shifted by 0.210 eV upon phase transition from the crystal to smectic A LC phases, indicating that PL tuning can also be achieved by controlling the aggregated structure. These results offer a new molecular design for easily tunable PL materials using the molecular properties or external stimuli for promising applications, including light-emitting displays and PL sensing materials.

Synthesis and characterization of novel liquid and liquid crystalline phthalocyanines

2004 ◽  
Vol 08 (10) ◽  
pp. 1175-1186 ◽  
Author(s):  
Mahmut Durmuş ◽  
Colette Lebrun ◽  
Vefa Ahsen
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Metal Salt ◽  
Electronic Spectroscopy ◽  
Scanning Calorimetry ◽  
Elemental Analyses ◽  
Columnar Mesophases ◽  
New Compounds ◽  
Hexagonal Columnar

Peripheral and non-peripheral tetra(13,17-dioxanonacosane-15-hydroxy) substituted metal free-, Ni (II) and Zn (II) phthalocyanines have been synthesized from the corresponding phthalonitrile derivatives in the presence of the anhydrous metal salt ( NiCl 2 and Zn ( OOCCH 3)2) or a strong organic base. The new compounds have been characterised by elemental analyses, IR, NMR, mass spectra and electronic spectroscopy. The mesogenic properties of these new materials were studied by differential scanning calorimetry (DSC), optical polarised microscopy and X-ray investigations. The effects of peripheral or non-peripheral substitution of (13,17-dioxanonacosane-15-hydroxy) to the phthalocyanine ring are also investigated. It is found out that non-peripheral substituted phthalocyanine derivatives (4a-c) are liquid at room temperature whereas, peripheral substituted phthalocyanine derivatives (7a-c) exhibit ordered discotic hexagonal columnar mesophases ( Col h) at room temperature.

scholarly journals Design of polar self-assembling lactic acid derivatives possessing submicrometre helical pitch

2018 ◽  
Vol 9 ◽  
pp. 333-341 ◽  
Author(s):  
Alexej Bubnov ◽  
Cyril Vacek ◽  
Michał Czerwiński ◽  
Terezia Vojtylová ◽  
Wiktor Piecek ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Scanning Calorimetry ◽  
Alkyl Chains ◽  
Temperature Range ◽  
Helical Pitch ◽  
Self Assembling ◽  
Electro Optic ◽  
Nanoscale Level

Several new lactic acid derivatives containing the keto linkage group far from the chiral part and short alkyl chains have been synthesized and characterised by polarising optical microscopy, differential scanning calorimetry, as well as electro-optic and dielectric spectroscopy. The materials possess a self-assembling behaviour on the nanoscale level as they form polar smectic liquid crystalline mesophases, namely the orthogonal paraelectric SmA* and the tilted ferroelectric SmC* phases, in a broad temperature range down to room temperature. A short helical pitch (≈120–320 nm), relatively high spontaneous polarisation (≈150 nC/cm2) and reasonable tilt angle values have been determined within the temperature range of the tilted ferroelectric SmC* phase. The obtained results make the new materials useful for the advanced mixture design and for further utilisation in electro-optic devices based on the deformed helix ferroelectric effect.

scholarly journals Synthesis and helical supramolecular organization of discotic liquid crystalline dibenzo[hi,st]ovalene

2019 ◽  
Vol 7 (41) ◽  
pp. 12898-12906 ◽  
Author(s):  
Qiang Chen ◽  
Wojciech Zajaczkowski ◽  
Johannes Seibel ◽  
Steven De Feyter ◽  
Wojciech Pisula ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Supramolecular Organization ◽  
Hexagonal Columnar

Novel dibenzo[hi,st]ovalene derivative (DBOV-TDOP) was synthesized to show an ordered helical hexagonal columnar assembly at room temperature.

scholarly journals Aggregation-Enhanced Room-Temperature Phosphorescence from Au(I) Complexes Bearing Mesogenic Biphenylethynyl Ligands

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7255
Author(s):  
Andriani Furoida ◽  
Misato Daitani ◽  
Kyohei Hisano ◽  
Osamu Tsutsumi
Keyword(s):  
Liquid Crystalline ◽  
Room Temperature ◽  
Crystal Size ◽  
Molecular Geometry ◽  
Quantum Yields ◽  
Room Temperature Phosphorescence ◽  
Alkyl Chains ◽  
Aurophilic Interactions ◽  
Linear Coordination

Gold(I) complexes, enabling to form linear coordination geometry, are promising materials for manifesting both aggregation-induced emission (AIE) behavior due to strong intermolecular Au–Au (aurophilic) interactions and liquid crystalline (LC) nature depending on molecular geometry. In this study, we synthesized several gold(I) complexes with rod-like molecular skeletons where we employed a mesogenic biphenylethynyl ligand and an isocyanide ligand with flexible alkoxyl or alkyl chains. The AIE behavior and LC nature were investigated experimentally and computationally. All synthesized gold(I) complexes exhibited AIE properties and, in crystal, room-temperature phosphorescence (RTP) with a relatively high quantum yields of greater than 23% even in air. We have demonstrated that such strong RTP are drastically changed depending on the crystal-size and/or crystal growth process that changes quality of crystals as well as the aggregate structure, of e.g., Au–Au distance. Moreover, the complex with longer flexible chains showed LC nature where RTP can be observed. We expect these rod-like gold(I) complexes to have great potential in AIE-active LC phosphorescent applications such as linearly/circularly polarizing phosphorescence materials.

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