The York Research Database

Herein we report studies on a bimesogen that exhibits a chiral twist bend nematic phase when doped with small weight percentages of a chiral material and a partial phase diagram constructed. At low concentrations a wide temperature range blue phase is observed, whereas at higher concentrations an additional 'nematic-like' mesophase was discovered at a lower temperature than the twist-bend nematic phase. In addition to an apparent isotropic-"isotropic" transition, the doped materials also exhibited a weakly birefringent phase upon annealing in the isotropic liquid phase, implying pretransitional behaviour in the same vein as that seen for TGB phases. When confined in a planar aligned cell, the N<inf>TB</inf> phase exhibited two domains that alternated between light and dark with rotation of the sample stage, as well as the application of an external electric field. Upon the addition of a chiral dopant one of these domains was eliminated, leading to their assignment as twist domains of opposite handedness.