Supermolecular Structure and Optical Properties

The optical properties of chiral nematic phases are closely related to their supermolecular Structures, as stated by the considerations of de Vries. In particular, the planar textures exhibit beautiful colors correlated to the pitch P of the helicoidal structures by Eq. (1), if the selective reflection wavelength lies in the visible range, and many examples are shown in Fig. 2. 

Hydroxypropyl cellulose (HPC) is the most widely studied lyotropic LC cellulose derivative. Werbowyj and Gray discovered the lyotropic LC state for cellulosics of this derivative [43]. HPC exhibits poor solubility and problems occur with handling at a molecular dispersed level, even at low concentration. However, HPC has the advantage of being commercially available and is able to dissolve in water, hence rheological studies can be carried out with the large amount of materials needed. It has the dis- 

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