Polymer liquid crystals in solution

Lydia Fritz, Joachim Rubner, Jurgen Springer and Dietmar Woljf 

Mechanical and Thermophysical Properties of Polymer Liquid Crystals Edited by W. Brostow 

Also for polymer solutions, the properties depend on interactions between solvent and dissolved components and vary strongly with concentration and temperature. Therefore, beside the molecular analysis, there is the important question for the understanding of the relationship between structure and properties, whether and how PLCs in a solution can be distinguished from those containing non-liquid crystalline polymers with a similar molecular architecture. Another interesting question is, to what extent the conformation of the macromolecules in solution is influenced by interactions between mesogenic groups. As a consequence of that, the hydro- and thermodynamic properties of the solution should also be affected. 

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. 

The LC state supposes rigid and anisometric shaped molecules. In MCPLCs the mesogens form the polymer backbone, while in SGPLCs the mesogenic groups are components of the side groups. In addition to this fundamental difference there are a great number of structural variations [1]. 

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