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Rational Design of Rod‐Like Liquid Crystals Exhibiting Two Nematic Phases
Author(s) -
Mandle Richard J.,
Cowling Stephen J.,
Goodby John W.
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201702742
Subject(s) - liquid crystal , biaxial nematic , degenerate energy levels , materials science , phase transition , polar , phase (matter) , condensed matter physics , crystallography , scattering , optics , chemistry , physics , organic chemistry , optoelectronics , quantum mechanics , astronomy
Recently, a polar, rod‐like liquid‐crystalline material was reported to exhibit two distinct nematic mesophases (termed N and N X ) separated by a weakly first‐order transition. Herein, we present our initial studies into the structure–property relationships that underpin the occurrence of the lower‐temperature nematic phase, and report several new materials that exhibit this same transformation. We have prepared material with significantly enhanced temperature ranges, allowing us to perform a detailed study of both the upper‐ and lower‐temperature nematic phases by using small‐angle X‐ray scattering. We observed a continuous change in d spacing rather than a sharp change at the phase transition, a result consistent with a transition between two nematic phases, structures of which are presumably degenerate.