Structure of Ions in Liquid-Crystalline Materials

1998 ◽  
Vol 508 ◽  
Author(s):  
Shohei Naemura ◽  
Yuji Nakazono ◽  
Kenichi Nishikawa ◽  
Atsushi Sawada ◽  
Peer Kirsch ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Ac Conductivity ◽  
Liquid Crystalline ◽  
Diffusion Constant ◽  
Isotropic Liquid ◽  
Crystalline Materials ◽  
Dc And Ac Conductivity ◽  
Steady State Current ◽  
Stokes Radius ◽  
Liquid Crystalline Materials

AbstractBoth steady-state current and dielectric-loss measurements were performed on a liquid-crystalline material, 4-(trans-4-pentylcyclohexyl)benzonitryl, in an isotropic liquid phase, which provide information on generation and behavior of ions, dominating DC and AC conductivity, respectively. The frequency dependence measurements of dielectric-loss can successfully estimate such characteristics of ions as total quantity of electricity, diffusion constant (mobility), and the size. With help of chemical analysis like ion chromatography and semi-empirical quantum chemical computation, the majority of ions, especially dominating AC conductivity, were estimated to be inorganic cations with Stokes' radius of around 2 × 10−8(cm), either naked or hydrated, and solvated ions with Stokes' radius of around 5 × 10−8(cm), most probably with the liquid-crystalline molecules at the solvation number of 1.2 in average. The present microscopic investigation of conduction mechanism is of great help for development of liquid-crystalline materials, especially for use in sophisticated displays with excellent picture quality.

Universal Scaling of Alpha Relaxation in Complex Liquids

2001 ◽  
Vol 56 (12) ◽  
pp. 893-894 ◽  
Author(s):  
A. Kurbatov ◽  
A. Drozd-Rzoska ◽  
S. J. Rzoska ◽  
M. Paluch ◽  
P. Malik ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Dielectric Relaxation ◽  
Liquid Crystalline ◽  
Isotropic Phase ◽  
Scaling Analysis ◽  
Crystalline Materials ◽  
Universal Scaling ◽  
Molecular Glass ◽  
Complex Liquids ◽  
Liquid Crystalline Materials

Abstract A plot is given, showing the result of a scaling analysis of dielectric loss curves containing, apart from low molecular glass former data (glycerol, dibutyl phtalate), also loss curves of the following liquid crystalline materials, mostly in the iso­ tropic phase: 4-(2-methylbutyl)-4'cyanobiphenyl (5*CB, supercooled isotropic phase), 4-cyano-4-n-alkyl biphenyls (nematogens 5CB and 8CB, isotropic phase), 4-(4-cyano-4-butylcyclohexyl)-4'-octylbiphenyl (laterally substituted nema-togen, isotropic phase), and 4-n-alkyl-4'-isothiocyanatobiphe-nyl (5 and 10 BT, isotropic and SmE phases). The plot applies the scaling formula originally proposed for glassforming, super­ cooled liquids [Dendzik et al.7]. The result supports the recent suggestion that dielectric relaxation in the isotropic phase of nematogens may show some features typical for "glassy" mate­ rials.

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...

Orthoconic antiferroelectric liquid crystalline materials

2005 ◽  
Vol 72 (9) ◽  
pp. 655
Author(s):  
K. Czuprynski ◽  
J. Gasowska ◽  
M. Tykarska ◽  
P. Kula ◽  
E. Sokól ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Crystalline Materials ◽  
Liquid Crystalline Materials
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