Liquid crystals thermotropic, hydrogen bonding

Ringsdorf s research group have prepared novel types of rigid-rod polyesters and polyamides 56 with a disc-like mesogen in tte mainchain [75]. Most polymers with six lateral substituents appear to be thermotropic liquid crystals. Polyamides with Z = H and having four substituents on the diamine component are not liquid crystalline. The two substituents on the diacid component seem to contribute to decrease further the intermolecular hydrogen bonding. 

In Sect. 5.1.2 it was shown, that two things are necessary for the formation of the lyotropic analog of the SmC phase. Firstly, the surfactant molecule has to exhibit a very balanced structure inbetween the structure of conventional thermotropic and lyotropic liquid crystals. Especially, the lyotropic part has to incorporate a polar chain with oxygen atoms connecting the diol head group to the rest of the molecule. Secondly, the solvent has to possess at least two hydrogen bond donor atoms... 

Koh, K. N., Araki, K., Komoii, T., Shinkai, S. (1995), Thermotropic liquid-crystal construction through the hydrogen-bonds between a stilbazole calix[4]arene and carboxylic-acids. Tetrahedron Letters, 36, 5191-4. 

A new type of thermotropic supramolec-ular liquid crystal obtained by molecular recognition processes through hetero-inter-molecular hydrogen bonds, which function between different and independent molecules species, were reported by Kato and Frechet [11-13] and Lehn and co-workers [14,15] in 1989 and 1993. After these findings, a wide variety of structures of molecular complexes has been prepared by supra-molecular self-assembly. 

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