Here, we report the mechanisms of chiral transfer at various length scales in the self-assembly of enantiomeric chiral block copolymers (BCPs*). We show the evolution of homochirality from molecular chirality into phase chirality in the self-assembly of the BCPs*. The chirality of the molecule in the BCP* is identified from circular dichroism (CD) spectra, while the handedness of the helical conformation in the BCP* is determined from a split-type Cotton effect in vibrational circular dichroism spectra. Microphase separation of the BCP* is exploited to form a helical (H*) phase, and the handedness of helical nanostructure in the BCP* is directly visualized from transmission electron microscopy tomography. As examined by CD and fluorescence experiments, significant induced CD signals and a bathochromic shift of fluorescence emission for the achiral perylene moiety as a chemical junction of the BCPs* can be found while the concentration of the BCPs* in toluene solution is higher than the critical micelle concentration, suggesting a twisting and shifting mechanism initiating from the microphase-separated interface of the BCPs* leading to formation of the H* phase from self-assembly.

Stereoregular vinyl polymers, poly(2-vinyl pyridine)s (P2VPs), were synthesized to examine the tacticity effect on the induced circular dichroism (ICD) via association with chiral acids. The ICD was found to be strongly dependent on the isotacticity of the P2VPs and the acidity of chiral acid in addition to its bulkiness.

The self‐assembly of 1,3‐phenylene bis[4‐(4‐n‐heptyloxybenzoyloxy)‐benzoates] (BC7) is studied to examine the formation of helical morphologies from achiral banana‐shaped liquid crystal molecules at different self‐assembling levels. Various hierarchical superstructures including flat‐elongated lamellar crystal, left‐ and right‐handed helical ribbons, and tubular texture are observed while the BC7 molecules self‐assemble in THF/H2O solution. By contrast, only plate‐like morphology is observed in the self‐assembly of achiral linear shaped 1,4‐phenylene bis[4‐(4‐n‐heptyloxybenzoyloxy)‐benzoates] (LC7) molecules, indicating that the chirality of the self‐assembled texture is strongly dependent upon the molecular geometry of the achiral molecules. The formation of the helical superstructures, namely hierarchical chirality, is attributed to the conformational chirality from the achiral banana‐shaped liquid crystalline molecules, as evidenced by significant optical activity in time‐resolved circular dichroism experiments. Selective area electron diffraction is performed to examine the structural packing of the hierarchical superstructures. As observed, the molecular disposition of the lamellar crystal is identical to that of the helical superstructure. Also, the diffraction patterns of the helical superstructures appeared arc‐like patterns consisting of a series of reflections, suggesting that the helical morphology resulted from the curving of the lamellar crystals through a twisting and bending mechanism. Consequently, the model of molecular disposition in the self‐assembled helical superstructures from the achiral banana‐shaped molecules is proposed. The morphological evolution in this study may provide further understanding with respect to the chiral information transfer mechanism from specific molecular geometry to hierarchical chirality in the achiral banana‐shaped molecules.

Herein, two asymmetric chiral bent-core molecules, 3-[(4-{[4-(heptyloxy)benzoyl]oxy}benzoyl)oxy]-phenyl-4-[(4-{[(1R)-1-methylheptyl]oxy}benzoyl)oxy] benzoate (BC7R) and 3-[(4-{[4-(heptyloxy)benzoyl]oxy}benzoyl)oxy]-phenyl-4-[(4-{[(1S)-1-methylheptyl]oxy}benzoyl)oxy] benzoate (BC7S), were synthesized to demonstrate control of the helicity of their self-assembled hierarchical superstructures. Mirror-imaged CD spectra showed a split-type Cotton effect after the formation of self-assembled aggregates of BC7R and BC7S, thereby suggesting the formation of intermolecular exciton couplets with opposite optical activities. Both twisted and helical ribbons with preferential helicity that corresponded to the twisting character of the intermolecular exciton couplet were found in the aggregates. The formation of helical ribbons was attributed to the merging of twisted ribbons through an increase in width to improve morphological stability. As a result, control of the helicity of hierarchical superstructures from the self-assembly of bent-core molecules could be achieved by taking advantage of the transfer of chiral information from the molecular level onto the hierarchical scale.

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