All-organic liquid crystalline radicals with a spin unit in the outer position of a bent-core system

2016 ◽  
Vol 4 (48) ◽  
pp. 11540-11547 ◽  
Author(s):  
K. Bajzíková ◽  
M. Kohout ◽  
J. Tarábek ◽  
J. Svoboda ◽  
V. Novotná ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Organic Liquid ◽  
Long Range Order ◽  
Core System ◽  
Liquid Crystalline Phases ◽  
System P ◽  
The Individual ◽  
Outer Position

All-organic paramagnetic liquid crystals offer the advantage of a long-range order of liquid crystalline phases and the magnetic properties of the individual molecules.

Magnetic Properties of All-Organic Liquid Crystals Containing a Chiral Five-Membered Cyclic Nitroxide Unit within the Rigid Core

2004 ◽  
Vol 116 (28) ◽  
pp. 3763-3768 ◽  
Author(s):  
Naohiko Ikuma ◽  
Rui Tamura ◽  
Satoshi Shimono ◽  
Naoyuki Kawame ◽  
Osamu Tamada ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Liquid Crystals ◽  
Organic Liquid ◽  
Rigid Core

scholarly journals Y-shaped tricatenar azobenzenes – functional liquid crystals with synclinic–anticlinic transitions and spontaneous helix formation

2020 ◽  
Vol 8 (37) ◽  
pp. 12902-12916 ◽  
Author(s):  
Mohamed Alaasar ◽  
Silvio Poppe ◽  
Yu Cao ◽  
Changlong Chen ◽  
Feng Liu ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Mirror Symmetry ◽  
Liquid Crystalline ◽  
Crystalline Phases ◽  
Helix Formation ◽  
Liquid Crystalline Phases ◽  
Bicontinuous Cubic

The photoisomerizable functional azobenzene unit is organized in synclinic hexatic, anticlinic smectic and bicontinuous cubic liquid crystalline phases as well as in achiral or mirror symmetry broken isotropic network liquids.

scholarly journals Mesoscale structure of wrinkle patterns and defect-proliferated liquid crystalline phases

2020 ◽  
Vol 117 (8) ◽  
pp. 3938-3943 ◽  
Author(s):  
Oleh Tovkach ◽  
Junbo Chen ◽  
Monica M. Ripp ◽  
Teng Zhang ◽  
Joseph D. Paulsen ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Primary Source ◽  
Fixed Number ◽  
Coarse Grained ◽  
Buffer Zones ◽  
Ginzburg Landau ◽  
Mesoscale Structure ◽  
Liquid Crystalline Phases ◽  
Chiral Liquid Crystals

Thin solids often develop elastic instabilities and subsequently complex, multiscale deformation patterns. Revealing the organizing principles of this spatial complexity has ramifications for our understanding of morphogenetic processes in plant leaves and animal epithelia and perhaps even the formation of human fingerprints. We elucidate a primary source of this morphological complexity—an incompatibility between an elastically favored “microstructure” of uniformly spaced wrinkles and a “macrostructure” imparted through the wrinkle director and dictated by confinement forces. Our theory is borne out of experiments and simulations of floating sheets subjected to radial stretching. By analyzing patterns of grossly radial wrinkles we find two sharply distinct morphologies: defect-free patterns with a fixed number of wrinkles and nonuniform spacing and patterns of uniformly spaced wrinkles separated by defect-rich buffer zones. We show how these morphological types reflect distinct minima of a Ginzburg–Landau functional—a coarse-grained version of the elastic energy, which penalizes nonuniform wrinkle spacing and amplitude, as well as deviations of the actual director from the axis imposed by confinement. Our results extend the effective description of wrinkle patterns as liquid crystals [H. Aharoni et al., Nat. Commun. 8, 15809 (2017)], and we highlight a fascinating analogy between the geometry–energy interplay that underlies the proliferation of defects in the mechanical equilibrium of confined sheets and in thermodynamic phases of superconductors and chiral liquid crystals.

Liquid Crystalline System

2017 ◽  
pp. 190-216
Author(s):  
Nayan Ashok Gujarathi ◽  
Bhushan Rajendra Rane ◽  
Raj K. Keservani
Keyword(s):  
Drug Delivery ◽  
Liquid Crystal ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Stable Phase ◽  
Science And Engineering ◽  
Liquid Crystalline Phases ◽  
Molecular Scale ◽  
Crystalline System ◽  
Liquid Crystalline System

Liquid crystalline system is a thermodynamically stable phase which is characterized by anisotropy. Liquid Crystals (LCs) are also termed as mesophase as they exhibit isotropic properties and liquid like behavior under some conditions (alter in temperature and concentration). Liquid crystals are influenced by number of parameters includes concentration, temperature, pH, and presence of salt. Liquid crystals are divided on the basis of shape of the molecules into two groups one is calmitic and other is discotic. A range of liquid crystalline phase (called mesophases) can be categorized by their sort of arrangement. The alignment of fragments in liquid crystalline phases is extensive on the molecular scale. Liquid crystal technology has a most important influence on several areas of pharmacy science and engineering, as well as device technology. As a novel type of drug delivery system, liquid crystals are explored and examined, definitely achieve mounting significance in industrial and scientific purposes.

scholarly journals Chemical-Physical Characterization of a Binary Mixture of a Twist Bend Nematic Liquid Crystal with a Smectogen

Crystals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1110
Author(s):  
Abir Aouini ◽  
Maurizio Nobili ◽  
Edouard Chauveau ◽  
Philippe Dieudonné-George ◽  
Gauthier Damême ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Nematic Liquid Crystal ◽  
Liquid Crystalline ◽  
Smectic A ◽  
Liquid Crystalline Phases ◽  
Electro Optic ◽  
Optical Dielectric

Nematic twist-bend phases (NTB) are new types of nematic liquid crystalline phases with attractive properties for future electro-optic applications. However, most of these states are monotropic or are stable only in a narrow high temperature range. They are often destabilized under moderate cooling, and only a few single compounds have shown to give room temperature NTB phases. Mixtures of twist-bend nematic liquid crystals with simple nematogens have shown to strongly lower the nematic to NTB phase transition temperature. Here, we examined the behaviour of new types of mixtures with the dimeric liquid crystal [4′,4′-(heptane-1,7-diyl)bis(([1′,1″-biphenyl]4″-carbo-nitrile))] (CB7CB). This now well-known twist-bend nematic liquid crystal presents a nematic twist-bend phase below T ≈ 104 °C. Mixtures with other monomeric alkyl or alkoxy -biphenylcarbonitriles liquid crystals that display a smectic A (SmA) phase also strongly reduce this temperature. The most interesting smectogen is 4′-Octyl-4-biphenylcarbonitrile (8CB), for which a long-term metastable NTB phase is found at room and lower temperatures. This paper presents the complete phase diagram of the corresponding binary system and a detailed investigation of its thermal, optical, dielectric, and elastic properties.

Synthesis and Mesomorphism of Novel Star-Shaped Liquid Crystals Containing Donor-Acceptor Groups

2013 ◽  
Vol 395-396 ◽  
pp. 72-75 ◽  
Author(s):  
Dan Shu Yao ◽  
Jun He ◽  
Guo Hua Li ◽  
Qian Xu ◽  
Ying Gang Jia ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Phase Behavior ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
H Nmr ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Liquid Crystalline Phases ◽  
Temperature Ranges ◽  
Donor Acceptor

A new class of three-armed star-shaped liquid crystals 5a-5d were synthesized, they used 1,3,5-trihydroxybenzene as a core, ω-[4-(p-ethoxybenzoloxy) phenoxycarbonyalkyl acid (3a, 3b) and ω-[4-(p-nitrobenzoloxy) phenoxycarbonyalkyl acid (3c, 3d) as mesogenic arms. Their chemical structures were confirmed by FTIR and 1H NMR spectra. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and thermogravimetric analyzer (TG) measurements. The results showed that the three-armed star-shaped liquid crystals exhibited a broad range of liquid crystalline phases at moderate temperature. The mesogenic arm structures obviously affected the phase behavior. As the intermedius alkyl chain of the star-shaped compounds lengthened (from n=4 to n=8), their melting points decreased but mesomorphic temperature ranges increased. The temperatures when 5% weight loss occurred (td) were higher than 300°C, which revealed that the synthesized three-armed liquid crystals had a high thermal stability. Threadlike, droplet and schlieren texture, typical of nematic phase can be observed in the liquid crystalline state during heating or cooling process.

scholarly journals Colloidal Lyotropic Liquid Crystalline Phases of Two-Dimensional Nanoparticles of Layered Hybrid Organic-Inorganic Metal Halide Perovskites

2021 ◽  
Author(s):  
PEI-XI WANG
Keyword(s):  
Liquid Crystals ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Metal Halide ◽  
Lyotropic Liquid Crystals ◽  
Two Dimensional ◽  
Halide Anion ◽  
Crystalline Phases ◽  
Liquid Crystalline Phases ◽  
Halide Perovskites

Lyotropic liquid crystals are fluids with macroscopic anisotropic structures formed by the self-assembly of nonspherically-symmetric mesogenic molecules or nanoparticles. Here, lyotropic liquid crystalline phases with discotic-nematic orderings were observed in colloidal dispersions of hexagonal-shaped nanoplatelets of two-dimensional layered hybrid organic-inorganic metal halide perovskites (with formula A<sub>2</sub>BX<sub>4</sub> where A<sup>1+</sup> is an organic ammonium cation, B<sup>2+</sup> is a divalent metal cation, and X<sup>1-</sup> is a halide anion) synthesized via microcrystallization by mixing precursor solutions with antisolvents containing surfactants, which showed semiconducting properties such as blue to green photoluminescence. As nanocrystalline perovskites are compositionally (transition metals like manganese, copper or europium as octahedral unit centers, mixed halides, organic spacers with chirality, etc.), microscopic structurally (three-, two-, or one-dimensional), and geometrically (nanosheets or nanorods) adjustable, liquid crystals with different phase behaviors and physical features (e.g., paramagnetism) may be systematically developed using this method.<br>

scholarly journals Colloidal Lyotropic Liquid Crystalline Phases of Two-Dimensional Nanoparticles of Layered Hybrid Organic-Inorganic Metal Halide Perovskites

2021 ◽  
Author(s):  
PEI-XI WANG
Keyword(s):  
Liquid Crystals ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Metal Halide ◽  
Lyotropic Liquid Crystals ◽  
Two Dimensional ◽  
Halide Anion ◽  
Crystalline Phases ◽  
Liquid Crystalline Phases ◽  
Halide Perovskites

Lyotropic liquid crystals are fluids with macroscopic anisotropic structures formed by the self-assembly of nonspherically-symmetric mesogenic molecules or nanoparticles. Here, lyotropic liquid crystalline phases with discotic-nematic orderings were observed in colloidal dispersions of hexagonal-shaped nanoplatelets of two-dimensional layered hybrid organic-inorganic metal halide perovskites (with formula A<sub>2</sub>BX<sub>4</sub> where A<sup>1+</sup> is an organic ammonium cation, B<sup>2+</sup> is a divalent metal cation, and X<sup>1-</sup> is a halide anion) synthesized via microcrystallization by mixing precursor solutions with antisolvents containing surfactants, which showed semiconducting properties such as blue to green photoluminescence. As nanocrystalline perovskites are compositionally (transition metals like manganese, copper or europium as octahedral unit centers, mixed halides, organic spacers with chirality, etc.), microscopic structurally (three-, two-, or one-dimensional), and geometrically (nanosheets or nanorods) adjustable, liquid crystals with different phase behaviors and physical features (e.g., paramagnetism) may be systematically developed using this method.<br>

Sign in / Sign up

Export Citation Format

Share Document