ABSTRACT
Herein, an epoch-making method based on bottom-up templating is proposed for the fabrication of a chiral nanoporous film that provides a chiral environment in which to confine nematic liquid crystals. A helical nanofilamental network of bent-core molecules was utilized as a three-dimensional mold, and thus the fabricated chiral nanoporous film has an inverse nanohelical structure. The presence of a chiral superstructure was confirmed by the observation of circular dichroism signals. Upon refilling this chiral nanoporous film with an achiral nematic liquid crystal, distinct circular dichroism signals appeared due to the transfer of chirality from the inverse helical nanofilaments to the achiral nematic liquid crystal. The circular dichroism signals can be readily modulated by external stimuli, such as the application of heat or an electric field. In addition, by refilling the chiral nanoporous film with a nematic liquid crystal doped with fluorescent dye, it exhibits stimuli-responsive circularly polarized luminescence. The proposed approach has huge potential for practical applications, such as for chiroptical modulators and switches and biological sensors.
ABSTRACT
A liquid crystal laser using a polymer-stabilized simple cubic blue phase (BPII) platform has been scarcely reported because the polymer stabilization of a BPII is relatively difficult compared to that of a body-centered-cubic BP (BPI). In this study, we succeeded in fabricating a dye-doped polymer-stabilized BPII laser with wide operating-temperature ranges over 15 °C including room temperature. A narrow and sharp single laser peak with a full width at half maximum of approximately 2 nm was derived from the photonic band edge effect of the BPII-distributed feedback optical resonator. As a result, the laser emission was a circularly polarized light, which matched the chirality of the proposed pure BPII.
