Side group polymer liquid crystals

Fig. 34. Examples of side-group polymer liquid crystals I - mesogenic group, II - spacer, III - backbone. The terminology side-group is used for (a), side-on fixed is used for (b), end-on fixed for (c) and side-chain for (d).

In the following, attention is focused only on some results obtained for solutions of thermotropic PLCs, and particularly on those of side group polymer liquid crystals (SGPLCs) since main chain polymer liquid crystals (MCPLCs) are normally difficult to dissolve and at least are insoluble in non-protonated solvents. The inclusion of lyotropic systems would be beyond the scope of this chapter and also would give no contribution to solving the question of how the properties of solutions of PLCs differ from those of non-LC polymers with similar molecular design. 

Portugall et al. (1982) noticed that the phase transition temperature and enthalpy of the following side-group type liquid crystal polymer, (3.13), were dependent on the degree of polymerization n. The polymer was noncrystalline. If n = 13, the glass transition temperature was 53 °C, the clearing point of the liquid crystal phase was 100 °C, the enthalpy of... 

The interaction of carboxylic acids affects the molecular order of side-chain polymer liquid crystals [130]. Copolymerization of an acrylate containing a cyanobiphenyl unit through butyl group and acrylic acid leads to the induction of a smectic A phase. The intra- and intermolecular H-bonds of carboxylic groups stabilize layered structures. 

Behavior and Properties of Side Group Thermotropic Liquid Crystal Polymers... 

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