Thermotropic liquid crystal polymers fundamentals

J. C. Dubois, P. Le Barny, M. Mauzac, and C. Noel, Behavior and Properties of Side Group Thermotropic Liquid Crystal Polymers, in Handbook of Liquid Crystals, Fundamentals high regular weigt liquid crystal, Vol. 3, Chapter II, D. Demus, J. W. Goodby, G. W. Gray, H. W. Spiess, and V. Vill (Eds.), pp. 207-277, Wiley VCH, New York. (1998). 

A common feature of different types of liquid crystal polymers (LCPs), e.g., thermotropic side-chain or main-chain (either stiff or with flexible spacers) polymers, is their slowed-down dynamics compared to low molecular weight liquid crystals (LCs). Often polymers can be quenched to a glassy state in which the liquid-crystalline order is preserved but motions are completely frozen out. Such liquid-crystalline glasses provide a unique opportunity to determine, in principle, the full orientational distribution function, whereas only its second moment is available from motionally averaged NMR spectra. Thus LCP studies have made fundamental contributions to LC science. 

The second group comprises thermotropic polymers. The phase transitions of thermotropic liquid crystals are achieved when a determined temperature range is reached. The fundamental unit that induces structural order in this kind of polymer presents with high rigidity and anisotropic shape [26,27]. Two major subclasses can be distinguished according to this shape discotic (disc-Uke molecules) and... 

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