Does Topology Dictate the Incidence of the Twist-Bend Phase? Insights Gained from Novel Unsymmetrical Bimesogens

Abstract

We prepared a significant number of unsymmetrical liquid-crystalline dimers that exhibit the twist-bend nematic phase; a state of matter that exhibits spontaneous breaking of mirror symmetry and, for some materials, a microsecond electrooptic response. A number of novel unsymmetrical bimesogens were synthesized and in comparing their thermal behaviour to previous literature examples, we have uncovered an unexpected relationship between the thermal stability of the nematic and NTBphases. This relationship demonstrates that molecular shape dictates the incidence of this fascinating phase of matter and leads us to speculate as to the existence of “twist-bend nematic phases” on length scales beyond those of the molecule.