Liquid-crystalline order

In conclusion, the different thermal histories imposed to PTEB have a minor effect on the /3 and y relaxations, while the a. transition is greatly dependent on the annealing of the samples, being considerably more intense and narrower for the specimen freshly quenched from the melt, which exhibits only a liquid crystalline order. The increase of the storage modulus produced by the aging process confirms the dynamic mechanical results obtained for PDEB [24], a polyester of the same series, as well as the micro-hardness increase [22] (a direct consequence of the modulus rise) with the aging time. 

Papkov, S. P. Liquid Crystalline Order in Solutions of Rigid-Chain Polymers. Vol. 59, pp. 75— 102. 

Blumstein, A., Liquid Crystalline Order in Polymers , Academic Press, N. Y., 1978... 

Schneider NS, Desper CR,Beres JJ (1978) In Blumstein A (ed) Liquid crystalline order in polymers. Academic, New York, chap 9, p 299... 

Similar to the sitnation with DNA structures formed under osmotic stress, DNA strands in cation-condensed bundles were found to be hexagonally packed and to possess liqnid crystalline order. For example, spermine and spermidine-condensed samples were fonnd to contain a cholesteric phase [70]. Surprisingly, DNA condensed with (Co(NH3)6) failed to exhibit a liquid crystalline ordering [47]. 

Rod-like micelles of surfactant molecules with a liquid-crystalline order. The aqueous solution is located between the micelles. Spheres = hydrophilic ends of the surfactant molecules, black zigzag lines = long alkyl groups... 

Blumstein, A., ed.. Liquid Crystalline Order in Polymers, Academic Press, New York, 1978. Cifferi, A., Kriegbaum, W.R., and Meyer, R.B., eds.. Polymer Liquid Crystals, Aeademie Press, New York, 1982. 

Leforestier, A. and Livolant, F. (1997) Liquid crystalline ordering of nucleosome core particles under macromolecular crowding conditions evidence for a discotic columnar hexagonal phase. Biophys. J. 73, 1771-1776. 

Sixou et al. (101) showed the circular dichroism of cholesteric CTA solutions in TFA depends on the CTA molecular weight. The intensity of the circular dichroic peak increases with molecular weight. Meeten and Navard (97) studied gel formation and liquid crystallinity in TFA-H2O solutions of CTA. When water was added to a liquid crystalline solution of CTA in TFA a gel phase formed presumably by the formation of crosslinks due to hydrogen bonding. They interpreted their results that liquid crystalline ordering involves both inter- and intramolecular forces. 

When the glass transition temperature of the polymer sample is reached in the DSC experiment, the plot will show an incline. It is obvious that the heat capacity increases at T, and therefore DSC can monitor the of a polymer. Usually the middle of the incline is taken to be the Tg. Above Tg, the polymer chains are much more mobile and thus might move into a more ordered arrangement they may assume crystalline or liquid-crystalline order. When polymers self-or-ganize in that way, they give off heat which can be seen as an exothermal peak in... 

A general concept for describing all kinds of order in chain molecules, ranging from crystalline order to liquid crystalline order and then to order in oriented and isotropic amorphous polymers, is introduced in the third article written by Pieper and Kilian. After the presentation of the basic concept, experimental results obtained on different polymers including phases with rotatory segmental motion are discussed. 

For a summary of lyotropic polypeptide glasses see E. T. Samuels, Liquid crystalline order in polypeptides in A. Blumstein, ed. Liquid Crystalline Order in Polymers . Academic Press, New York, NY 1978. For the description of glasses of dicholesterylesters of dicarboxylic acids see D. Gross, Z, Naturforsch. B27, 472 (1972)... 

In plastic crystals or PC-glasses one looks for positional order and an absence of orientational order. While for liquid crystalline order it is almost self-understood... 

---