Monodomain alignment of the smectic-A liquid crystalline phase from the isotropic phase

2008 ◽  
Vol 104 (4) ◽  
pp. 044902 ◽  
Author(s):  
Mitya Reznikov ◽  
Bentley Wall ◽  
Mark A. Handschy ◽  
Philip J. Bos
Keyword(s):  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Isotropic Phase ◽  
Smectic A

Dynamics of liquid crystalline phase transition in sedimenting platelet-like particles

Soft Matter ◽  
2018 ◽  
Vol 14 (16) ◽  
pp. 3049-3056 ◽  
Author(s):  
Jize Sui ◽  
Yiming Ding ◽  
Masao Doi
Keyword(s):  
Phase Transition ◽  
Crystalline Phase ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Isotropic Phase ◽  
Closed Container ◽  
Crystalline Phase Transition

When a suspension of platelet-like particles sediment in a closed container, the particles undergo isotropic–nematic phase transition (I–N transition), and there appears a clear interface between the isotropic phase and the nematic phase.

Two-Dimensional Superlattice Self-Formed by Novel Ionic Liquid Crystals and Its Photofunctional Property

1999 ◽  
Vol 559 ◽  
Author(s):  
A. Kanazawa ◽  
T. Ikeda
Keyword(s):  
Liquid Crystals ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Chloride Ions ◽  
Liquid Crystalline Phase ◽  
Two Dimensional ◽  
Phosphonium Salts ◽  
Smectic A ◽  
Transition Behavior ◽  
Smectic A Phase

ABSTRACTThermotropic liquid-crystalline behavior of various complex salts, which are structurally simple amphiphiles without rigid cores, was evaluated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffractometry. The phosphonium salts, consisting of positive phosphorus and negative chloride ions, were found to show a smectic A phase in which a homeotropic structure was formed spontaneously. It is significant that the phosphonium salts possess an advantageous feature as thermotropic liquid crystals and show a stable liquid-crystalline phase and a simple phase transition behavior in comparison with commonly available ammonium analogs. Furthermore, the introduction of divalent metal ions into the amphiphiles was revealed to result in enhancement of the thermal properties. Although the ammonium chlorides as parent compounds showed no liquid-crystalline phase (or indistinct transition behavior), the ammonium complexes possessing tetrachlorometalate ions exhibited clearly the smectic A phase in the expanded temperature range. Additionally, through the evaluation of dipolar alignment in the solid-state phosphonium assembly by second harmonic generation, it was assumed that the self-assembly can be regarded as layered polar thin films produced by two-dimensional ionic layers with an overall permanent electric polarization.

Amphiphilic Carbohydrate-Based Mesogens, 12 [1] High-Yield Synthesis of Mesogenic 1-O-Alkanoyl-D/L-Xylitols

1996 ◽  
Vol 51 (9) ◽  
pp. 1229-1234 ◽  
Author(s):  
Wilhelm V. Dahlhoff ◽  
Karin Radkowski ◽  
Ingo Dierking ◽  
Peter Zugenmaier
Keyword(s):  
Crystalline Phase ◽  
Vacuum Distillation ◽  
Liquid Crystalline ◽  
Equilibrium Mixture ◽  
Liquid Crystalline Phase ◽  
High Yield ◽  
Smectic A

The equilibrium mixture of 1,2:3,4- and 1,3:2,4-di-O-ethylboranediyl-D/L-xylitols 1 and 1′ obtained on reaction of three equivalents of xylitol with two equivalents of triethylboroxin, reacts with alkanoyl chlorides (heptanoyl-dodecanoyl) to give equilibrium mixtures of the O-ethylboranediyl protected l-O-alkanoyl-D.L-xylitols 2,2′ after vacuum distillation. Deprotection of the latter affords the title amphiphilic esters 3 which melt to give the smectic A liquid-crystalline phase.

Amphiphilic Carbohydrate-Based Mesogens, 10. Synthesis of Mesogenic 2-O-n-Alkyl-L-threitols

1995 ◽  
Vol 50 (3) ◽  
pp. 405-410 ◽  
Author(s):  
Wilhelm V. Dahlhoff ◽  
Karin Radkowski ◽  
Peter Zugenmaier ◽  
Ingo Dierking
Keyword(s):  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Smectic A ◽  
Amphiphilic Compounds

Dimethyl-L-tartrate 1 is converted into 2,3-O-n-heptylidene-decylidene dimethyl-L-tartrates 2 which are reduced with ethyldiboranes alone and then in the presence of 9-methylsulfonyloxy- 9-borabicyclo[3.3.1]nonane (MSBBN ) to yield 2-O -alkyl-L -threitols 4, after deprotection. The amphiphilic compounds 4 are thermotropic mesogens which display the smectic A liquid crystalline phase on melting.

scholarly journals Amphiphilic Carbohydrate-Based Mesogens, 11 Synthesis of Mesogenic 1-AIkylthio-1-deoxy-D-galactitols by Glycoside Reduction

1995 ◽  
Vol 50 (7) ◽  
pp. 1079-1085 ◽  
Author(s):  
Wilhelm V. Dahlhoff ◽  
Karin Radkowski ◽  
Klaus Riehl ◽  
Peter Zugenmaier
Keyword(s):  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase ◽  
Smectic A

Alkyl-1-thio-α/β-D-gaIactopyranosides (hexyl-dodecyl, 1a - g ) have been O-diethylborylated and then reduced with tetraethyldiboranes(6) in the presence of 9-methylsulfonyloxy- 9-borabicyclo[3.3.1]nonane (MSBBN) catalyst to give 1-alkylthio-1-deoxy-D-galactitols 3a -g after deprotection. 3 exhibit the smectic A liquid crystalline phase on melting.

Processing Natural and Reconstituted Silk Solutions Under Equilibrium and Non-Equilibrium Conditions

1992 ◽  
Vol 292 ◽  
Author(s):  
Christopher Viney ◽  
Anne E. Huber ◽  
Dwayne L. Dunaway ◽  
Steven T. Case ◽  
David L. Kaplan
Keyword(s):  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Aquatic Insect ◽  
Liquid Crystalline Phase ◽  
Isotropic Phase ◽  
Insect Larvae ◽  
Equilibrium Conditions ◽  
Wide Range ◽  
Anisotropic Structures

AbstractA variety of natural silk secretions (from spiders, silkworms and aquatic insect larvae), and also reconstituted silk solutions, are able to form a nematic liquid crystalline phase. The anisotropic structures that self-assemble in this phase are formed from the isotropic phase by aggregation of molecules, rather than by individual molecules undergoing a conformational change to a rod-like form. This enables the molecules to retain their solubility in water while, simultaneously, the viscosity of the solution is reduced. The liquid crystalline phase is stable under a wide range of equilibrium conditions, but its ability to form is sensitive to the rate at which the initially isotropic solution is allowed to dry. The kinetics of phase transitions exhibited by solutions of silk proteins must be taken into account if solutions of silk fibroin are to be successfully processed in vitro.

scholarly journals Electron transfer studies of a conventional redox probe in human sweat and saliva bio-mimicking conditions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Krishnaveni ◽  
V. Ganesh
Keyword(s):  
Electron Transfer ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Transfer Reaction ◽  
Electron Transfer Reaction ◽  
Redox Couple ◽  
Liquid Crystalline Phase ◽  
Transfer Reactions ◽  
Redox Probe ◽  
Human Sweat

AbstractModern day hospital treatments aim at developing electrochemical biosensors for early diagnosis of diseases using unconventional human bio-fluids like sweat and saliva by monitoring the electron transfer reactions of target analytes. Such kinds of health care diagnostics primarily avoid the usage of human blood and urine samples. In this context, here we have investigated the electron transfer reaction of a well-known and commonly used redox probe namely, potassium ferro/ferri cyanide by employing artificially simulated bio-mimics of human sweat and saliva as unconventional electrolytes. Typically, electron transfer characteristics of the redox couple, [Fe(CN)6]3−/4− are investigated using electrochemical techniques like cyclic voltammetry and electrochemical impedance spectroscopy. Many different kinetic parameters are determined and compared with the conventional system. In addition, such electron transfer reactions have also been studied using a lyotropic liquid crystalline phase comprising of Triton X-100 and water in which the aqueous phase is replaced with either human sweat or saliva bio-mimics. From these studies, we find out the electron transfer reaction of [Fe(CN)6]3−/4− redox couple is completely diffusion controlled on both Au and Pt disc shaped electrodes in presence of sweat and saliva bio-mimic solutions. Moreover, the reaction is partially blocked by the presence of lyotropic liquid crystalline phase consisting of sweat and saliva bio-mimics indicating the predominant charge transfer controlled process for the redox probe. However, the rate constant values associated with the electron transfer reaction are drastically reduced in presence of liquid crystalline phase. These studies are essentially carried out to assess the effect of sweat and saliva on the electrochemistry of Fe2+/3+ redox couple.

Liquid crystalline phase transitions in hexakis(4-(4′-heptyloxy)biphenoxy)cyclotriphosphazene

1995 ◽  
Vol 18 (5) ◽  
pp. 795-800 ◽  
Author(s):  
K. Moriya ◽  
H. Mizusaki ◽  
M. Kato ◽  
S. Yano ◽  
M. Kajiwara
Keyword(s):  
Phase Transitions ◽  
Crystalline Phase ◽  
Liquid Crystalline ◽  
Liquid Crystalline Phase
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