Photoprogrammable Mesogenic Soft Helical Architectures: A Promising Avenue toward Future Chiro‐Optics

Abstract

reflection, exhibits photonic localization in the band gap determined by the period in the case of normal incidence. [6] Similarly, a helical superstructure composed of chiral chromophores leads to absorption differences between left-and right-handed CPL, referred to as the Cotton effect, owing to the asymmetry of chiral chromophores or that of achiral chromophores induced by a chiral system. [7] Chiro-optical characteristics in helical supramolecular assemblies and superstructures have attracted tremendous attention in the past decade, especially in self-organized mesogenic helical soft matter, which is an emerging scientific frontier in chemistry, functional materials, soft matter physics, biological medicine, and even sensor physics. Mesogenic soft matter, defined as soft condensed matter with molecules containing single or multiple anisotropic mesogen moieties, is distinct from common soft condensed matter in terms of molecular arrangement, interaction, and specific optical chirality, although the "soft" characteristic is still maintained. A primary reason for the softness is related to the responses of this type of matter to multiple external stimuli, such as electric fields, heat, light, mechanical forces, and even acoustic fields. [8] The control and manipulation of such soft materials by light is always more desirable than that of other stimuli due to the prominent advantages of non-contact, wireless, remote, and high-resolution control, which enable numerous unprecedented chiro-optical applications. [9] Optically, another fascinating feature of these materials is their molecular self-organization behavior, which can establish an ordered and regular arrangement with a structural parameter (≈µm) much larger than the single-molecule scale (≈nm) through the weak non-covalent molecular interaction, rather than the chemical bonds that normally exist in

Engineering Achiral Liquid Crystalline Polymers for Chiral Self-Recovery

“…Similarly, introducing mirror symmetry breaking into LCs will commonly result in multitudinous chiral LC phases, such as the chiral nematic (N*) [ 29 , 30 ], chiral smectic (S*) [ 31 ], twist grain boundary (TGB) [ 32 ] and cubic blue phases [ 33 ], which have been well investigated in small molecular LCs. As reported by Li et al [ 34 , 35 , 36 ], the sign and the magnitude of the N*-LCs pitches are strongly governed by chiral dopants due to their good fluidity. From another point of view, good fluidity is often accompanied by poor stability and a strong dependence on chiral resources.…”

Controlling Mirror Symmetry Breaking and Network Formation in Liquid Crystalline Cubic, Isotropic Liquid and Crystalline Phases of Benzil‐Based Polycatenars

“…[69] It is noted that there is as trong relationb etween the Cub bi -Iso [ * ] transitions reported here for achiral molecules (with transiently chiral conformations) and the BPI/BPIItoB PIII (BP = blue phase) transition observed for permanently chiral rod-likem olecules. [71,72] The cubic BPII, for example, has a Ia3 d double gyroid structure, whereas the BPIII (blue fog phase) is an isotropic liquid with dynamic network structure. [71a] Even the typical DSC features of the BPI/BPII to BPIII transitions resemble those of the Cub bi -Iso [ * ] transitions, characterizedb yabroad diffuse feature in the liquid state.…”

“…[73,74] Figure 11 summarizes the relations between molecular structure and formation of the distinct cubic and accompanying mirror symmetryb roken Iso 1 [ * ] phases gained herein. Overall, this work contributes to the better understanding of the development of networks and spontaneousm irror symmetry breaking in self-assembled systems, including crystalline helical aggregates, [43,[64][65][66][67][68][69][70][71][72][73][74][75] gels, [60,66] LC phases [38,59,60,62,[76][77][78][79] and Figure 11. Summary of the relationsb etween molecular structure, cubic phaset ype,cubic phase stability and mirror symmetry breaking in the LC and isotropic liquid phases.…”

“…[73,74] Figure 11 summarizes the relations between molecular structure and formation of the distinct cubic and accompanying mirror symmetryb roken Iso 1 [ * ] phases gained herein. Overall, this work contributes to the better understanding of the development of networks and spontaneousm irror symmetry breaking in self-assembled systems, including crystalline helical aggregates, [43,[64][65][66][67][68][69][70][71][72][73][74][75] gels, [60,66] LC phases [38,59,60,62,[76][77][78][79] and the most intriguing case of mirror-symmetry broken isotropic liquids. [47] In general,t he nano-structures of the liquid phases and their polyamorphism( liquid-liquidp hase transitions and liquid-liquid phase separations) are still less investigated and represent almost unsolved scientific problemsw ith great importance.…”

3D Chiral Photonic Nanostructures Based on Blue‐Phase Liquid Crystals

“…[ 56–63 ] In this regard, 1D photonic superstructures based on cholesteric liquid crystals (CLCs) have been extensively investigated and widely applied in reflective displays, tunable lasers, and other advanced chiral photonic devices. [ 64–79 ] Blue‐phase liquid crystals (BPLCs) with cubic lattice nanostructures have recently entered the research limelight due to their ability to self‐organize into 3D chiral photonic crystals that can manipulate light or the flow of photons in all the three dimensions. [ 80–85 ] Herein, we present a comprehensive review of the state‐of‐the‐art in 3D chiral photonic nanostructures based on BPLCs and their potential applications.…”