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Abstract The range of possible morphologies for bent‐core B4 phase liquid crystals has recently expanded from helical nanofilaments (HNFs) and modulated HNFs to dual modulated HNFs, helical microfilaments, and heliconical‐layered nanocylinders. These new morphologies are observed when one or both aliphatic side chains contain a chiral center. Here, the following questions are addressed: which of these two chiral centers controls the handedness (helicity) and which morphology of the nanofilaments is formed by bent‐core liquid crystals with tris‐biphenyl diester core flanked by two chiral 2‐octyloxy side chains? The combined results reveal that the longer arm of these nonsymmetric bent‐core liquid crystals controls the handedness of the resulting dual modulated HNFs. These derivatives with opposite configuration of the two chiral side chains now feature twice as large dimensions compared to the homochiral derivatives with identical configuration. These results are supported by density functional theory calculations and stochastic dynamic atomistic simulations, which reveal that the relative difference between thepara‐ andmeta‐sides of the described series of compounds drives the variation in morphology. Finally, X‐ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) data also uncover the new morphology for B4 phases featuringp2/msymmetry within the filaments and less pronounced crystalline character.
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Heliconical-layered nanocylinders (HLNCs) – hierarchical self-assembly in a unique B4 phase liquid crystal morphology
A unique morphology for bent-core liquid crystals forming the B4 phase has been found for a class of tris-biphenyl bent-core liquid crystal molecules with a single chiral side chain in the longer para -side of the molecule. Unlike the parent molecules with two chiral side chains or a chiral side chain in the shorter meta -side, which form helical nano- or microfilament B4 phases, the two derivatives described here form heliconical-layered nanocylinders composed of up to 10 coaxial heliconical layers, which can split or merge, braid, and self-assemble into a variety of modes including feather- or herringbone-type structures, concentric rings, or hollow nest-like superstructures. These multi-level hierarchical self-assembled structures, rivaling muscle fibers, display blue structural color and show immense structural and morphological complexity.
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- Award ID(s):
- 1659571
- PAR ID:
- 10160209
- Date Published:
- Journal Name:
- Materials Horizons
- Volume:
- 6
- Issue:
- 5
- ISSN:
- 2051-6347
- Page Range / eLocation ID:
- 959 to 968
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/C9MH00089E
