Helical structures were confirmed for both the SmA b and SmBlue phases of banana-shaped molecular systems from observations of the microscopic fringe pattern and the selective reflection of blue color, respectively. X-ray and optical microscopy indicate that the helical axes in the SmA b and SmBlue phases are normal and parallel to the smectic layer, respectively. In these two helical phases, 13C NMR spectra show two C=O peaks, suggesting two different configurations of ester group, whereas only one C=O peak appears in the isotropic and crystal phases. This indicates that the two C=O groups in the mesogenic core are not in the same plane but are twisted. The addition of chiral dopant makes the dichroic ratio of the right- and left-circularly polarized scattered light positive or negative in the SmBlue phase, although the wavelength (∼430 nm) of the scattering peak does not change significantly. The origin of the helix will be discussed in view of the twisted molecular conformation (conformational chirality) and the escape from macroscopic polarization.

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Imperative irradiation: A large enantiomeric excess in a liquid‐crystal phase can be induced by circularly polarized light (CPL) as an external stimulus, and an imbalance in the two chiral domains becomes remarkable in the BX phase (see pictures), which is similar to the B4 phase made up by classical bent‐core mesogens.

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A simple methodology is developed to realize chiroptical function induced through superstructural chirality of a matrix of helical nanofilaments formed by achiral molecules. In this work, circularly polarized luminescence is demonstrated in nanosegregated mesophase comprising only achiral molecules. An achiral molecular mixture of a bent-core host and a rod-like guest blended with a fluorescent dye is prepared. Circularly polarized luminescence confirms that the chiral superstructure consisting only of achiral molecules may serve as a chiral super nanospace for inducing chiral emissions from the fluorescent dye that exhibits rod-like molecular ordering. In other words, the formation of a chiral superstructure by the segregated rod-like molecules embedded in helical nanofilaments (bent-core molecules) is confirmed. The results provide a novel strategy for constructing dissymmetric circularly polarized luminescence materials based on achiral molecules, which is potentially applicable in future information and display technologies.