Main chain crystalline polymers

Certain phenyl-linked polymers (32) that exhibit mesophase behaviour will have elements of the structures shown below  

These oligomeric methyl-substituted p-phenylenes have an axial ratio (x) equal to 0.8 times the number of benzene rings. According to theory predictions hexamethylhexphenyl (n = 1) which has x = 4.8 and lower oligomers should not exhibit a mesophase, whereas octamethyloctphenyl (n = 2) has x = 6.4, i.e. larger than the critical value of 6.2, and exhibits a nematic phase. A variety of other systems with phenylene structures have been explored whilst they have 

Substituted polyesters (33) as a consequence of the conjugation through the ester function can exhibit the required characteristics of hquid crystalline behaviour. 

This series of polymers illustrates the breadth to length criteria and demonstrates that only those systems that form a crystalline phase exhibit mesophase behaviour. 

Rod-like soluble polyimides (34) have been shown to exhibit liquid crystalline characteristics. All polymers containing alkyl side chains of identical 

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Utilization of the single hydrogen bond between pyridine and benzoic acids in SLCP s has been a source of inspiration for other groups in the development of main-chain supramolecular polymers based on diacids and dipyridines.53-56 Supramolecular rod-coil polymers have been developed by assembly of 4,4 -bipyridines and telechelic polypropylene oxide with benzoic acid end-groups, which show highly ordered liquid crystalline phases.57 The use of tartaric acid derivatives in combination with bipyridine units resulted in the formation of hydrogen-bonded, chiral main-chain LCP s, as has been shown by circular dichroism measurements, optical microscopy, and X-ray data.58,59... 

Han HS, Bhowmik PK (1995) Liquid-crystalline main-chain ionene polymers. Trends Polym... 

Bhowmik PK, Akhter S, Han H (1995) Thermotropic liquid-crystalline main-chain viologen polymers. J Polym Sci A Polym Chem 33 1927-1933... 

The 1-nylons or poly(alkyl isocyanates) give liquid crystalline polymers which may make them useful for electrical applications. These polymers are characterized as main-chain mesogenic polymers having a semirigid structure. 

The liquid crystallinity in main-chain LC polymers is associated with molecular chains that are uniformly stiffer than those in conventional polymers. This stiffness or rigidity is usually achieved by increasing the aromatic content (e.g., benzene tings) and coimecting the groups so as to increase chain straightness. 

Alderman N, Mackley M (1985) Optical textures observed during the shearing of thermotropic liquid-crystal polymers. Faraday Discuss Chem Soc 79 149-160 Antoun S, Lenz RW, Jin I (1981) Liquid crystal polymers. IV. Thermotropic polyesters with flexible spacers in the main chain. J Polym Sci Polym Chem Ed 19 1901-1920 Baek SG, Magda JJ, Cementwala S (1993) Normal stress differences in liquid crystalline hydroxypropyl cellulose solutions. J Rheol 37 935-945 Barnes HA (2003) A review of the rheology of filled viscoelastic systems. In The British Society of Rheology, pp 1-36... 

As shown by Huser and Spiess," " the liquid-crystalline nature of the main chain disc polymer containing the units... 

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