Intermediate liquid crystalline phases in the binary system C16TACl-H2O: an NMR and low-angle x-ray diffraction study

1992 ◽  
Vol 96 (9) ◽  
pp. 3894-3902 ◽  
Author(s):  
Ulf Henriksson ◽  
Eunice S. Blackmore ◽  
Gordon J. T. Tiddy ◽  
Olle Soederman
Keyword(s):  
Binary System ◽  
Diffraction Study ◽  
Liquid Crystalline ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray ◽  
Liquid Crystalline Phases

Single crystal X-ray structure determination and temperature-dependent structural studies of the smectogenic compound 7OS5

2020 ◽  
Vol 76 (6) ◽  
pp. 1128-1135
Author(s):  
Aleksandra Deptuch ◽  
Teresa Jaworska-Gołąb ◽  
Joachim Kusz ◽  
Maria Książek ◽  
Keigo Nagao ◽  
...  
Keyword(s):  
Single Crystal ◽  
Homologous Series ◽  
Liquid Crystalline ◽  
Temperature Phase ◽  
Smectic Layer ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
Layer Spacing ◽  
X Ray ◽  
Liquid Crystalline Phases

Structural characteristics of solid and liquid crystalline phases of 7OS5 (4-n-pentylphenyl-4′-n-heptyloxythiobenzoate), the achiral smectogenic mesogen with the shortest terminal carbon chain in the nOS5 homologous series, are studied by complementary methods. Simultaneously perfomed X-ray diffraction and differential scanning calorimetry occur to be a powerful tool to study metastable phases. The single crystal structure of a high-temperature phase, supercooled from the room temperature down to −183°C [orthorhombic crystal system; space group Pca21; a = 54.285 (5) Å, b = 5.5843 (3) Å, c = 14.841 (1) Å, Z = 8] is determined. Lamellar ordering of elongated molecules is stabilized by hydrogen bonds . Temperature dependence of unit-cell parameters in two crystal phases as well as structural parameters of liquid crystalline phases (smectic layer spacing, tilt angle, average distance between the long axes of molecules and correlation lengths) are determined by X-ray diffraction. The obtained results are compared with the data available for other compounds in the nOS5 homologous series.

scholarly journals SOME ELECTRON MICROSCOPICAL OBSERVATIONS ON LIQUID-CRYSTALLINE PHASES IN LIPID-WATER SYSTEMS

1962 ◽  
Vol 12 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Walther Stoeckenius
Keyword(s):  
Electron Micrographs ◽  
Liquid Crystalline ◽  
Water Systems ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
Thin Sections ◽  
X Ray ◽  
Liquid Crystalline Phases ◽  
Electron Microscopical ◽  
Good Agreement

OsO4 fixation preserves some liquid-crystalline phases of soaps and phospholipids to an extent that it is possible to observe their structure in electron micrographs of thin sections. Good agreement exists between the structure observed directly and that deduced from x-ray diffraction studies of the same systems.

Characterization of some mesogenic alkyl 1-thioglycosides

2002 ◽  
Vol 80 (8) ◽  
pp. 1162-1165 ◽  
Author(s):  
B Henrissat ◽  
G K Hamer ◽  
M G Taylor ◽  
R H Marchessault
Keyword(s):  
Phase Transition ◽  
Liquid Crystal ◽  
Solid State ◽  
Solid State Nmr ◽  
Liquid Crystalline ◽  
Liquid Crystal Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Liquid Crystalline Phases

A series of dodecyl 1-thio-β-D-glycosides has been synthesized and characterized (DSC, NMR, CP MAS, X-ray diffraction) as possible new marking materials with liquid-crystalline properties. These compounds undergo solid to liquid crystal phase transitions at various temperatures, which depend on the nature of the carbohydrate part of the structure. Their liquid-crystalline phases show extreme shear thinning behaviour.Key words: liquid crystal, powder X-ray diffraction, phase transition, thioglycoside, solid-state NMR, marking material

High-pressure X-ray diffraction study of the δ-phase in the uranium-neptunium binary system

1990 ◽  
Vol 2 (5-6) ◽  
pp. 255-261 ◽  
Author(s):  
S. Dabos-Seignon ◽  
E. Geeing ◽  
U. Benedict ◽  
J. C. Spirlet ◽  
M. Pagés
Keyword(s):  
High Pressure ◽  
Binary System ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Δ Phase

scholarly journals The Synthesis and Properties of Liquid Crystalline Polyurethanes, Chemically Modified by Polyhedral Oligomericsilsesquioxanes

Molecules ◽  
2019 ◽  
Vol 24 (22) ◽  
pp. 4013 ◽  
Author(s):  
Artur Bukowczan ◽  
Edyta Hebda ◽  
Maciej Czajkowski ◽  
Krzysztof Pielichowski
Keyword(s):  
Liquid Crystalline ◽  
Second Step ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Step Method ◽  
X Ray ◽  
Chemically Modified ◽  
Liquid Crystalline Phases ◽  
Breaking Points ◽  
First Time

In this work, we report for the first time on the influence of polyhedral oligomericsilsesquioxanes (POSS) on the structure and properties of liquid crystalline polyurethane (LCPU). LCPU/POSS hybrids were synthesized via a two-step method. In the first step, 4,4′-methylenephenyl diisocyanate (MDI) and polytetramethylene ether glycol (PTMG) reacted with functionalized trisilanolphenyl POSS (TSP-POSS) bearing three hydroxyl groups. In the second step, the growing chain was extended with 4,4′-bis(hydroxyhexoxy)biphenyl (BHHBP). FTIR measurements confirmed the chemical bonding between the POSS and LCPU matrix and showed the influence of the silsesquioxane modification on the intensity of hydrogen bonds. The DSC and POM techniques confirmed the formation of liquid crystalline phases. The incorporation of silsesquixanes into the LC matrix leads to higher melting and isotropization temperatures along with the broadening phase transition effect. Scanning electron microscopy showed a good distribution of POSS moieties, both in the bulk and on the surface of the liquid crystalline PU matrix, whereby wide-angle X-ray diffraction (WAXD) patterns revealed halos from both the liquid crystalline and unmodified polyurethane matrix. The stress at the breaking points for LCPU/POSS hybrids containing 50% and 60% of elastic segments is greater than the stress at the breaking point of the reference material (LCPU), what is due to good dispersion of POSS in less elastic matrix. Thermal properties of the LCPU/POSS materials obtained, determined by TGA, revealed that the char residue increased with the amount of POSS for 40% of elastic segments materials.

Study of the Liquid Crystalline Phases in Some Compounds of 4-Trans-(4-Alkyl)Cyclo-Hexylphenyl-Alkylcarboxylate

1983 ◽  
Vol 38 (12) ◽  
pp. 1362-1364 ◽  
Author(s):  
I. H. Ibrahim ◽  
W. Haase
Keyword(s):  
Differential Scanning Calorimetry ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Intermolecular Distance ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Enthalpy Changes ◽  
Liquid Crystalline Phases ◽  
Nematic Phases

Abstract Three mesogenic compounds of the general formula have been investigated by differential scanning calorimetry. thermal optical microscopy and X-ray diffraction methods/Enthalpy changes of The different phase transitions for these compounds have been determined. H33 exhibits smectic B and nematic phases, whereas H34 and H75 exhibit only smectic B phases. The thickness of the smectic layers and the average intermolecular distance have been evaluated, as well as the corresponding molecular parameters in the nematic phase.

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