Influence of alkoxy tail length on the phase behaviour of mesogen-jacketed liquid crystalline polymers with fan-shaped pendants

Polymer ◽  
2010 ◽  
Vol 51 (20) ◽  
pp. 4503-4510 ◽  
Author(s):  
Chang-An Yang ◽  
Guo Wang ◽  
He Lou Xie ◽  
Hai Liang Zhang
Keyword(s):  
Liquid Crystalline ◽  
Tail Length ◽  
Liquid Crystalline Polymers ◽  
Phase Behaviour ◽  
Crystalline Polymers

Liquid crystalline polymers

2004 ◽  
Author(s):  
Sangdil I. Patel ◽  
Fred J. Davis
Keyword(s):  
Liquid Crystalline ◽  
Main Chain ◽  
Liquid Crystalline Polymers ◽  
Phase Behaviour ◽  
Side Chain ◽  
Polymer Backbone ◽  
Crystalline Materials ◽  
Crystalline Polymers ◽  
Anisotropic Behaviour ◽  
Liquid Crystalline Materials

The idea of combining the anisotropic behaviour of liquid crystalline materials with the properties of macromolecular systems was first suggested by Onsanger and subsequently Flory. The actual realization that such systems could exist came from studies of natural polymers such as the tobacco mosaic virus. Interest in these systems intensified with the development of highstrength systems, based on rigid-rod systems, notably the aramid fibres, however, liquid crystallinity in such systems occurs only at high temperatures, usually close to the decomposition point of the polymer. It was only in the late 1970s that the design criteria for liquid crystalline polymers became apparent, the secret being largely in the decoupling of the rigid aromatic groups which give rise to the anisotropic behaviour. As a result of these ideas two classifications of liquid crystalline materials were described. Main-chain liquid crystalline polymers, are those in which rigid aromatic molecules form part of the polymer backbone, either as a continuous chain or separated by a series of methylene groups in order to lower temperature at which liquid crystalline phase behaviour is observed. Side-chain systems resemble the comb-like systems studied by Shibaev and Plate, and have the rigid aromatic groups attached as a side-chain. In general, the monomer systems required for main-chain liquid crystalline polymers are relatively simple; synthetically these systems are prepared by step-growth methods and the main challenge is often maintaining sufficient solubility to allow suitable chain-lengths to be grown (an example of how such problems might be overcome is given in Chapter 4). Side-chain systems tend to be produced from more complex structural sub-units, and may be produced either by polymerization of the appropriate monomer or by functionalization of a preformed polymer backbone. Examples of both approaches are given in this chapter. From a practical viewpoint, the advantage of side-chain systems is that they tend to be much more soluble in common organic solvents and also that thermal phase transitions occur at reasonable temperatures (reasonable being well below the temperature at which the polymer decomposes). A further advantage of such side-chain systems is that the phase behaviour can be effectively tuned through the chemical modifications of the three components, namely the side-group, the flexible coupling chain and the polymer backbone.

Influence of chirality on phase behaviour of side chain liquid crystalline polymers

1996 ◽  
Vol 37 (5) ◽  
pp. 625-629
Author(s):  
Xueping Jiang ◽  
Wenyan Guo ◽  
Zongneng Qi ◽  
Shufan Zhang
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Phase Behaviour ◽  
Side Chain ◽  
Crystalline Polymers

Influence of alkoxy tail length and unbalanced mesogenic core on phase behavior of mesogen-jacketed liquid crystalline polymers

2009 ◽  
Vol 47 (2) ◽  
pp. 505-514 ◽  
Author(s):  
Si Chen ◽  
Lan-Ying Zhang ◽  
Long-Cheng Gao ◽  
Xiao-Fang Chen ◽  
Xing-He Fan ◽  
...  
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Tail Length ◽  
Liquid Crystalline Polymers ◽  
Crystalline Polymers

Influence of alkoxy tail length on the phase behaviors of side-chain liquid crystalline polymers without the spacer

RSC Advances ◽  
2015 ◽  
Vol 5 (12) ◽  
pp. 9035-9043 ◽  
Author(s):  
Bin Ni ◽  
Junqiu Liao ◽  
Sheng Chen ◽  
Hai-liang Zhang
Keyword(s):  
Phase Behavior ◽  
Liquid Crystalline ◽  
Tail Length ◽  
Liquid Crystalline Polymers ◽  
Side Chain ◽  
Crystalline Polymers ◽  
Phase Behaviors

The alkoxy tail plays an important role in the phase behavior of the SCLCPs based on biphenyl mesogen without the spacer.

Structure-property relations of liquid crystalline polymers

1987 ◽  
Vol 45 ◽  
pp. 460-463
Author(s):  
Linda C. Sawyer
Keyword(s):  
Solid State ◽  
Liquid Crystalline ◽  
Structural Model ◽  
Crystalline Polymer ◽  
Liquid Crystalline Polymers ◽  
Mechanical Anisotropy ◽  
Structure Property ◽  
Preparation Methods ◽  
Crystalline Polymers ◽  
Extended Chain

Recent liquid crystalline polymer (LCP) research has sought to define structure-property relationships of these complex new materials. The two major types of LCPs, thermotropic and lyotropic LCPs, both exhibit effects of process history on the microstructure frozen into the solid state. The high mechanical anisotropy of the molecules favors formation of complex structures. Microscopy has been used to develop an understanding of these microstructures and to describe them in a fundamental structural model. Preparation methods used include microtomy, etching, fracture and sonication for study by optical and electron microscopy techniques, which have been described for polymers. The model accounts for the macrostructures and microstructures observed in highly oriented fibers and films.Rod-like liquid crystalline polymers produce oriented materials because they have extended chain structures in the solid state. These polymers have found application as high modulus fibers and films with unique properties due to the formation of ordered solutions (lyotropic) or melts (thermotropic) which transform easily into highly oriented, extended chain structures in the solid state.

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