scholarly journals Electric-field-induced molecular alignment of side-chain liquid-crystalline polyacetylenes containing biphenyl mesogens

2004 ◽  
Vol 42 (7) ◽  
pp. 1333-1341 ◽  
Author(s):  
Jianxin Geng ◽  
Enle Zhou ◽  
Gao Li ◽  
Jacky Wing Yip Lam ◽  
Ben Zhong Tang
Keyword(s):  
Electric Field ◽  
Liquid Crystalline ◽  
Molecular Alignment ◽  
Side Chain

Behavior of Liquid Crystalline Side Chain Polymers in an Electric Field

1983 ◽  
Vol 94 (3) ◽  
pp. 343-358 ◽  
Author(s):  
H. Finkelmann ◽  
U. Kiechle ◽  
G. Rehage
Keyword(s):  
Electric Field ◽  
Liquid Crystalline ◽  
Side Chain

Aggregation Structure and Electro—Optical Properties of (Liquid Crystalline Polymer)/(Low Molecular Weight Liquid Crystal) Composite System

1989 ◽  
Vol 171 ◽  
Author(s):  
Tisato Kajiyama ◽  
Hirotsugu Kikuchi ◽  
Akira Miyamoto ◽  
Satoru Moritomi ◽  
Jenn—Chiu Hwang
Keyword(s):  
Molecular Weight ◽  
Light Scattering ◽  
Electric Field ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Smectic Phase ◽  
Side Chain ◽  
Low Molecular Weight ◽  
Smectic Layer

ABSTRACTA series of thin films composed of liquid crystalline polymer (LCP) and low molecular weight liquid crystal (LMWLC) was prepared by a solventcasting method or by a bar—coating method. LCPs were of mesogenic side chain type with strong or weak polar terminalgroups in the side chain portion. A mixture of smectic LCP (LCP with side chain of strong polar end) and nematic LMWLC formed a smectic phase in a LCP weight fraction range above 50 %. Also, a mixture of nematic LCP (LCP with side chain of weak polar end) and nematic LMWLC with strong polar group induced a new smectic phase in a LCP molar fraction range of 20–80 %. Reversible and bistable electro-optical effects based on light scattering were recognized for a smectic phase of a binary composite composed of LCP and LMWLC. A light scattering state caused by many fragmented smectic lamellae appeared in the case of application of an a.c. electric field below a threshold frequency (∼l Hz). Furthermore, application of a 100 Vp—p a.c. field of 1 kHz made the transmission light intensity increased to 94 % within a few seconds. The optical heterogeneity in asmectic layer composed of the side chain group of LCP was caused by the difference of twoforces based on both dielectric anisotropy of the side chain and electrohydrodynamic motion of the main chain. Since application of a low frequency electric field causes an ioniccurrent throughout the mixture film, it is reasonable to consider that an induced turbulent flow of main chains by an ionic current collapsed a fairly well organized large smectic layer into many small fragments, resulting in an increase in light scattering. The response speed of LCP upon application of an electric field increased remarkably by mixingLMWLC. In the case of a smectic mesophase, turbid and transparent states remained unchanged as it was, even though after removing an electric field.1Such abistable and reversiblelight switching driven by two different frequencies of electric field could be newly realized by both characteristics of turbulent effect of a wellorganized large smectic layer of LCP and rapid response of LMWLC. We believe that the LCP/LMWLC mixture system is promissing as a novel type of “light valve” exhibiting memory effect (bistable light switching).

Side chain liquid crystalline polymers: Electric field effects and nonlinear properties

1995 ◽  
Vol 96 (1) ◽  
pp. 185-206 ◽  
Author(s):  
Dominique Gonin ◽  
Bertrand Guichard ◽  
Claudine Noël ◽  
François Kajzar
Keyword(s):  
Electric Field ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Electric Field Effects ◽  
Crystalline Polymers ◽  
Nonlinear Properties ◽  
Field Effects

ELECTRORHEOLOGICAL EFFECT OF LIQUID CRYSTALLINE POLYMERS

1996 ◽  
Vol 10 (23n24) ◽  
pp. 3191-3200 ◽  
Author(s):  
AKIO INOUE ◽  
SYUNJI MANIWA ◽  
YOICHIROH IDE ◽  
HIROJI ODA
Keyword(s):  
Shear Stress ◽  
Electric Field ◽  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Shear Stresses ◽  
Spacer Length ◽  
Crystalline Polymers ◽  
Electrorheological Effect ◽  
Base Polymer

A series of side chain liquid crystalline polymers (LCPs) containing different spacer length and various terminal structures has been prepared and their electrorheological (ER) effect has been investigated. Although the LCP itself showed small ER effect, a mixture of the LCP with a plain polydimethylsiloxane (PDMS) oil was found to show a large increase in shear stress upon application of an electric field. The shear stresses under DC 2 kV/mm of an electric field were 14 to 4 times those without the application of an electric field over the temperature range of 30 to 160 °C for a 2:1 mixture (by weight) of a LCP containing an oxyethylene spacer and a mesogen based on 4-cyanophenyl benzoate with PDMS. Two mechanisms responsible for the generation of the ER effect was suggested from the investigation using phenyl-substituted PDMS and an analysis by DSC: oriented LC network induction, and phase separation between the LC base polymer and PDMS.

scholarly journals Molecular alignment in liquid crystalline side chain polymers.

Kobunshi ◽  
1989 ◽  
Vol 38 (4) ◽  
pp. 270-273
Author(s):  
Kazuhide Saigo ◽  
Toyokazu Nakamura
Keyword(s):  
Liquid Crystalline ◽  
Molecular Alignment ◽  
Side Chain

Observing the relaxation of molecular orientation in sheared liquid crystalline polymer solutions

1990 ◽  
Vol 48 (4) ◽  
pp. 1092-1093
Author(s):  
Wendy Putnam ◽  
Christopher Viney
Keyword(s):  
Molecular Orientation ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Polymer Processing ◽  
Molecular Alignment ◽  
Global Alignment ◽  
Shear Direction ◽  
Axial Strength ◽  
Strength And Stiffness

Liquid crystalline polymers (solutions or melts) can be spun into fibers and films that have a higher axial strength and stiffness than conventionally processed polymers. These superior properties are due to the spontaneous molecular extension and alignment that is characteristic of liquid crystalline phases. Much of the effort in processing conventional polymers goes into extending and aligning the chains, while, in liquid crystalline polymer processing, the primary microstructural rearrangement involves converting local molecular alignment into global molecular alignment. Unfortunately, the global alignment introduced by processing relaxes quickly upon cessation of shear, and the molecular orientation develops a periodic misalignment relative to the shear direction. The axial strength and stiffness are reduced by this relaxation.Clearly there is a need to solidify the liquid crystalline state (i.e. remove heat or solvent) before significant relaxation occurs. Several researchers have observed this relaxation, mainly in solutions of hydroxypropyl cellulose (HPC) because they are lyotropic under ambient conditions.

Discotic columnar liquid-crystalline polymer semiconducting materials with high charge-carrier mobility via rational macromolecular engineering

2017 ◽  
Vol 8 (21) ◽  
pp. 3286-3293 ◽  
Author(s):  
Bin Mu ◽  
Xingtian Hao ◽  
Jian Chen ◽  
Qian Li ◽  
Chunxiu Zhang ◽  
...  
Keyword(s):  
Liquid Crystalline ◽  
Cost Effective ◽  
Crystalline Polymer ◽  
Charge Carrier Mobility ◽  
Optoelectronic Device ◽  
Side Chain ◽  
Liquid Crystal Polymers ◽  
Semiconducting Materials ◽  
Organic Semiconducting Materials ◽  
Device Applications

Well-prepared side-chain discotic liquid crystal polymers with shorter spacers in ordered columnar phases are fascinating and promising cost-effective, solution-processable organic semiconducting materials for various potential optoelectronic device applications.

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