Liquid Crystalline Zinc Chloride

1999 ◽  
Vol 559 ◽  
Author(s):  
J. D. Martin ◽  
T.A. Thornton
Keyword(s):  
Zinc Chloride ◽  
Liquid Crystalline ◽  
Lyotropic Liquid Crystals ◽  
Entire Family ◽  
Viscous Liquids ◽  
Crystalline Materials ◽  
Liquid Crystalline Phases ◽  
Zeolite Type ◽  
Inorganic Content ◽  
Liquid Crystalline Materials

ABSTRACTThe templated syntheses of our zeolite-type frameworks of metal halides frequently result in the formation of glassy phases or viscous liquids that might be described as ambient temperature molten salts. Having discovered that certain of these materials exhibit remarkable birefringence, we have investigated the structure of both the glass and liquid forms of alkylammonium templated zinc chloride materials by neutron and X-ray diffraction, as well as DSC and polarizing microscopy techniques. Further template control using alkylammonium surfactants as directors has yielded an entire family of liquid crystalline materials with up to 90% inorganic content. The compositional dependence of the structure of these liquid crystalline phases suggests that these materials are best described as “solvent-free” lyotropic liquid crystals.

The Dynamic Properites of Confined Antiferroelectric Liquid Crystal Investigated By Photon Correlation Spectroscopy

1999 ◽  
Vol 559 ◽  
Author(s):  
Yu.P. Panarin ◽  
C. Rosenblatr ◽  
F.M. Aliev
Keyword(s):  
Phase Transition ◽  
Porous Media ◽  
Liquid Crystalline ◽  
Photon Correlation Spectroscopy ◽  
Correlation Spectroscopy ◽  
Photon Correlation ◽  
Crystalline Materials ◽  
Liquid Crystalline Phases ◽  
Liquid Crystalline Materials ◽  
Structural Aspects

ABSTRACTDynamic light scattering was used to examine ferrielectric liquid crystalline phases in porous media. Whereas in larger pores (200 Å) ferrielectric phases were observed, they were not found in the smallest pores (200 Å). Additionally, the temperatures of SmC - SmA phase transition were found to be suppressed in the pores relative to bulk, while SmCA - SmCγ phase transition is not affected by the confinement. These observations have been explained by the structural aspects of antiferroelectric liquid crystalline materials in a confined geometry and show the importance of long range electrostatic interaction for existence of ferrielectric phases.

Synthesis of Dendrimers Liquid Crystalline Materials based on 1,3,5-triphenylbenzene

2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Linh I Awad ◽  
Nasreen R Jber
Keyword(s):  
Differential Scanning Calorimeter ◽  
Liquid Crystalline ◽  
Spectroscopic Method ◽  
Optical Microscope ◽  
Crystalline Materials ◽  
Liquid Crystalline Phases ◽  
Ft Ir ◽  
Liquid Crystalline Materials ◽  
New Compounds ◽  
Liquid Crystalline Dendrimers

In this study, new compounds of discotic liquid crystalline dendrimers are prepared which is derived from 1,3,5-triphenylbenzene. The synthesis of these compounds shows the effect of dendrimer unit on the mesogenic properties. The structures of prepared compounds characterized by using spectroscopic method e.g. FT-IR and 1HNMR. The liquid crystalline phases of prepared compounds was identified by using the hot-stage polarizing optical microscope (POM) and differential scanning calorimeter (DSC).

scholarly journals Artificial colloidal liquid metacrystals by shearing microlithography

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yanqiu Jiang ◽  
Fan Guo ◽  
Zhen Xu ◽  
Weiwei Gao ◽  
Chao Gao
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Molecular Size ◽  
Digital Design ◽  
Lyotropic Liquid Crystals ◽  
Colloidal Systems ◽  
Extended Form ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials ◽  
External Stimuli

Abstract Meta-periodicity beyond intrinsic atomic and molecular order, such as metacrystalline and quasicrystalline lattices, exists in solids, but is usually elusive in lyotropic liquid crystals for its energetic instability. The stable meta-periodicity in lyotropic liquid crystals in the absence of external stimuli remains unexplored, and how to achieve it keeps a great challenge. Here we create lyotropic liquid crystals with stable meta-periodicity in a free state, coined as liquid metacrystals, in colloidal systems by an invented shearing microlithography. The meta-periodicity is dynamically stabilized by the giant molecular size and strong excluded volume repulsion. Liquid metacrystals are designed to completely cover a library of symmetries, including five Bravais and six quasicrystalline lattices. Liquid metacrystal promises an extended form of liquid crystals with rich meta-periodicity and the shearing microlithography emerges as a facile technology to fabricate liquid meta-structures and metamaterials, enabling the digital design of structures and functionalities of liquid crystalline materials.

Liquid Crystalline Materials for Polymers with Anisotropic Ultrastructures

1989 ◽  
Vol 175 ◽  
Author(s):  
George S. Attard
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Lyotropic Liquid Crystals ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials

AbstractThe in-situ polymerisation of reactive thermotropic and lyotropic liquid crystals affords a method of processing new polymers with anisotropic ultrastructures.

Use of light microscopy in the qualitative and quantitative study of liquid crystalline order

1992 ◽  
Vol 50 (1) ◽  
pp. 264-265
Author(s):  
Christopher Viney
Keyword(s):  
Light Microscopy ◽  
Liquid Crystalline ◽  
Structural Characteristics ◽  
Molecular Order ◽  
Liquid Crystalline Phases ◽  
Convenient Technique ◽  
Liquid Crystalline Materials ◽  
Transparent Windows

Light microscopy is a convenient technique for characterizing molecular order in fluid liquid crystalline materials. Microstructures can usually be observed under the actual conditions that promote the formation of liquid crystalline phases, whether or not a solvent is required, and at temperatures that can range from the boiling point of nitrogen to 600°C. It is relatively easy to produce specimens that are sufficiently thin and flat, simply by confining a droplet between glass cover slides. Specimens do not need to be conducting, and they do not have to be maintained in a vacuum. Drybox or other controlled environmental conditions can be maintained in a sealed chamber equipped with transparent windows; some heating/ freezing stages can be used for this purpose. It is relatively easy to construct a modified stage so that the generation and relaxation of global molecular order can be observed while specimens are being sheared, simulating flow conditions that exist during processing. Also, light only rarely affects the chemical composition or molecular weight distribution of the sample. Because little or no processing is required after collecting the sample, one can be confident that biologically derived materials will reveal many of their in vivo structural characteristics, even though microscopy is performed in vitro.

On resolving fine periodic microstructures in the optical microscope

1989 ◽  
Vol 47 ◽  
pp. 364-365
Author(s):  
W.S. Putnam ◽  
C. Viney
Keyword(s):  
Liquid Crystalline ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Normal Incidence ◽  
Optical Microscope ◽  
Angle Of Incidence ◽  
Resolution Limit ◽  
Crystalline Materials ◽  
Periodic Microstructures ◽  
Liquid Crystalline Materials

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.

Designing Chemically Selective Liquid Crystalline Materials that Respond to Oxidizing Gases

2021 ◽  
Author(s):  
Nanqi Bao ◽  
Jake Gold ◽  
Tibor Szilvasi ◽  
Huaizhe Yu ◽  
Robert Twieg ◽  
...  
Keyword(s):  
Computational Methods ◽  
First Principles ◽  
Liquid Crystalline ◽  
Soft Materials ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials ◽  
Chemically Selective ◽  
Kinetics Of

Computational methods can provide first-principles insights into the thermochemistry and kinetics of reactions at interfaces, but this capability has not been widely leveraged to design soft materials that respond selectively...

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