Sanidic mesogen

Sanidic mesogen - a mesogen composed of molecules with board-like shapes. 

Tetrasubstituted polyesters with long alkyl side chains on the hydroquinone moiety connected via ether or ester linkages have been reported [20 c] (Fig. 12). In these polyesters, the tetrasubstituted moiety can be considered as a discotic mesogen. The polyesters with Z = H are highly soluble and have low melting temperatures (T n < 100 °C) and low clearing temperatures in the range of 123-260°C. The type of mesophase formed is referred to as sanid-... 

Calamitic and discotic compounds can be described theoretically using the same basic model, i.e. the cylinder, by elongation or compression, respectively, of the central axis of the cylinder [23]. Of course, the cylinder model is a oversimplification of real mesogenic molecules. As most of the compounds contain ring systems, which are somewhat flat, it could be proposed that parallelepipeds provide better models. In fact, such models have been used for molecular-statistical theories, and these have allowed the description of, in addition to calamitic and discotic molecules, flat elongated (board-like, sanidic) molecules [24]. 

Figure 1 Examples for mesogens that form caiamitic, discotic, or sanidic phases.

The sanidic mesophase results from a hindered rotation of the mesogenic units. It requires three distinctly different dimensions of the mesogens.This phase is generally observed in polymers with lateral side chains and very rarely in LMWLCs. In the case of polymers also the extension of the molecule in the direaion of the polymer chain contributes to a... 

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