Toward rational design of complex nanostructured liquid crystals

Abstract

An analogy of block copolymer micro-segregation as a low-molecular weight nanostructured liquid crystal (LC) was tested with recently found columnar and cubic phase-forming LC molecules, to clarify the broader applicability of the analogy as a molecular design principle. We found that the copolymer analogy principle also works well for new micellar cubic phase-forming molecules. For bicontinuous cubic phase-forming 1,2-bis(4'-n-alkoxybenzoyl)hydrazines (BABH-n) compounds that cover a much broader core fraction range than that predicted by the copolymer analogy, we propose hierarchical preferential orientation as an additional mechanism for their cubic range broadening. For azo-dichiral molecules that also do not fit with the above principle, we propose chiral segregation as an alternative origin for their cubic phase formation.

Chemical Programming of the Domain of Existence of Liquid Crystals

“…The Flory and Huggins theory, in terms of solubility parameters, shows that the latter interaction factor depends on ( δ A − δ B ) 2 weighted by the thermal energy . Quantitative applications to mesogenic calamitic cyanobiphenyls, cubic‐phase‐forming liquid‐crystalline molecules, and polycatenar pentaerythritol derivatives successfully rationalized phase segregation, leading to specific mesomorphism. However, contrary to Trouton's rule for the vaporization of liquids, the entropy changes, Δ S tr , accompanying the melting process that transforms a solid into a liquid or a liquid crystal, or the isotropization process that transforms a liquid crystal into an isotropic liquid, are not constant.…”

Nanostructured liquid-crystalline semiconductors – a new approach to soft matter electronics

“…33 Therefore, incompatible side chains with aromatic cores instead of alkyl chains can induce mesophases. In the classical description, LC phases appear as a result of strong interaction between the π-conjugated cores moderately weakened by thermal motion of the alkyl chains.…”

Cubic and Other3DThermotropic Liquid Crystal Phases and Quasicrystals

“…There is further evidence that imply connections between the SmQ phases and the bicontinuous cubic phases. In a review by Yoneya [156], it has been pointed out that by making the bicontinuous cubic Im3m structure chiral, the lattice distorts to the tetragonal, space group I422; at the same time, Ia3d becomes I4 1 22 and Pn3m becomes P4 2 22. Tetragonal distortion of the Ia3d phase (a = 76.7Å) to an I4 1 /acd symmetry (a = 73.2Å, c = 80.9Å) has in fact been observed for the racemic mixture mentioned earlier, adding support to the existence of a connection between bicontinuous cubic and SmQ structures [8].…”