Cholesteric liquid crystals, thermochromic

McDonnell, D. G. Thermochromic Cholesteric Liquid Crystals, in Thermotropic Liquid Crystals, Gray, G. W. (Ed.), Wiley, Chichester, 1987, Chapter 5, pp. 120-144. 

Figure 1.13 Schematic diagram showing how the pitch change of a thermochromic cholesteric liquid crystal.

In the pioneer paper published by Thierry and Skoulios [20], it was advanced that polypeptides with sufficient long polymethylene side chains could display liquid-crystalline phases upon melting of the side chain. They in fact reported a high temperature nematic phase that reversed upon cooling into a lower temperature phase, whose structure was not elucidated. Since then, a good amount of research has been made on comblike polyglutamates, with the focus mainly toward the development of thin films with thermochromic properties. The liquid-crystal structure anticipated for these systems should be cholesteric according to the chiral nature of the main chain a-helix. However other mesomorphs have been described under certain conditions and for certain side chain compositions. 

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