Liquid crystalline properties of dissymmetric molecules IX. The effect of a terminal nitro group on the thermal properties of the smectic A phase in 4-nitrophenyl 4-(4-alkoxybenzoyloxyphenyl)benzoates

2002 ◽  
Vol 29 (10) ◽  
pp. 1311-1319 ◽  
Author(s):  
Takeyasu Tasaka ◽  
Vladimir F. Petrov ◽  
Hiroaki Okamoto Yuki Morita ◽  
Kazuyuki Suetake ◽  
Shunsuke Takenaka
Keyword(s):  
Thermal Properties ◽  
Nitro Group ◽  
Liquid Crystalline ◽  
Smectic A ◽  
Smectic A Phase

NMR Relaxation Study of Molecular Dynamics in the Smectic A Phase of PAMAM Liquid Crystalline Dendrimers of Generation 1 and 3

2006 ◽  
Vol 450 (1) ◽  
pp. 191/[391]-201/[401] ◽  
Author(s):  
A. Van-Quynh ◽  
D. Filip ◽  
C. Cruz ◽  
P. J. Sebastião ◽  
A. C. Ribeiro ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Liquid Crystalline ◽  
Nmr Relaxation ◽  
Smectic A ◽  
Smectic A Phase ◽  
Relaxation Study ◽  
Liquid Crystalline Dendrimers

Syhthesis and Mesomorphic Properties of Side-Chain Liquid-Crystalline Polysiloxanes Exhibiting Spherulite Texture of Polymeric Smectic A Phase

2011 ◽  
Vol 26 (4) ◽  
pp. 437-442
Author(s):  
李颖 LI Ying ◽  
张广成 ZHANG Guang-cheng ◽  
刘斌 LIU Bin ◽  
蒋莹 JIANG Ying ◽  
孙伟民 SUN Wei-min
Keyword(s):  
Liquid Crystalline ◽  
Side Chain ◽  
Smectic A ◽  
Smectic A Phase ◽  
Mesomorphic Properties

Structure and Thermal Behaviour of a Thermotropic Liquid Crystalline Polyimide (PI-LC)

1998 ◽  
Vol 10 (1) ◽  
pp. 147-153 ◽  
Author(s):  
M Tanaka ◽  
M Konda ◽  
M Miyamoto ◽  
Y Kimura ◽  
A Yamaguchi
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Nematic Phase ◽  
Liquid Crystalline ◽  
Polarized Light ◽  
Isotropic Phase ◽  
X Ray ◽  
Smectic A ◽  
Smectic C ◽  
Smectic A Phase

Anomalous solid structures formed by a thermotropic liquid crystalline polyimide (PI-LC) were investigated by thermal analysis, polarized light microscopy and x-ray analysis. It was revealed that PI-LC should undergo a phase transition from the crystalline to the isotropic phase through the smectic or nematic phase in the temperature range 277–300 °C. The PI-LC filament extruded at 280 °C, at which temperature the polymer was in liquid crystalline phase, was formed to have a structure similar to the smectic C phase, while that extruded and melt-drawn at 310 °C, at which temperature the polymer was in the isotropic phase, had a structure similar to the smectic A 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.

Broad Temperature Range Of Chiral Smectic C Phase In Some Ferroelectric Side-Chain Liquid Crystalline Polysiloxanes Containing Oligooxyethylene Spacers

1993 ◽  
Vol 328 ◽  
Author(s):  
G. H. Hsiue ◽  
J. H. Chen ◽  
C. S. Hsu
Keyword(s):  
Liquid Crystalline ◽  
Side Chain ◽  
Diffraction Measurement ◽  
Cholesteric Phase ◽  
Temperature Range ◽  
Smectic A ◽  
Smectic C ◽  
Linkage Position ◽  
Smectic A Phase ◽  
The Stability

ABSTRACTThe Mesomorphic behaviors of some ferroelectric liquid crystalline monomers and side-chain polysiloxanes studied by X-ray diffraction Measurement, differential scanning calorimeter and polarizing Microscope. All obtained polymers exhibit wide temperature range of chiral smectic C phase including room temperature.These Mesogenic structures contain oligooxyethylene spacers and (S)-2-Methyl-l -butyl chiral tail via a three phenyl ester linkage (i.e. -Ph-COO-Ph-Ph- or -Ph-Ph-COO-Ph-). Two series of monomers with different biphenyl group linkage position were compared. One shows a novel twisted smectic A phase, in addition to the liquid crystalline sequence (Ch→SA→Sc*) obtained between cholesteric phase and smectic A phase. It also presents an unusual smectic A and chiral smectic C phase.All the prepared polymers present smectic Mesomorphism. As the unit of flexible oligooxyethylene spacers increases, the clearing temperature decreases and the stability of the smectic phase also increases.

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