Smectic assemblies in C₃-symmetric hexa-alkylated liquid crystals: transformation from smectogen to discogen via hydrogen bonding.

Park, Soyoung; Ryu, Mi-Hee; Shin, Tae Joo; Cho, Byoung-Ki · Soft Matter · 2014

basic_science · Level V

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Abstract

In this paper, we report a C3-symmetric liquid crystal (LC) with sixfold alkyl peripheries exhibiting an unusual smectic E-like organization in the LC state. Based on conformational considerations, the smectic assembly is attributed to the formation of an endo-type Y conformer of asymmetric triazolyl and benzylic groups that cannot be accessed in other C3-symmetric molecules exclusively showing columnar assemblies. The Y conformers form a two-dimensional oblique lattice in the aromatic layers of the ordered smectic phase. In addition, the Y-shaped molecule in the smectic phases can change into a circular shape by the 1 : 1 hydrogen-bonding interaction with a gallic acid derivative, which leads to a hexagonal columnar LC phase. The triazole-based LC design concept proves the smectic LC assembly in the C3-symmetric system, and provides the supramolecular manipulation of LC morphologies.