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Gowda A, Pathak SK, Rohaley GAR, Acharjee G, Oprandi A, Williams R, Prévôt ME, Hegmann T. Organic chiral nano- and microfilaments: types, formation, and template applications. MATERIALS HORIZONS 2024; 11:316-340. [PMID: 37921354 DOI: 10.1039/d3mh01390a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
Organic chiral nanofilaments are part of an important class of nanoscale chiral materials that has recently been receiving significant attention largely due to their potential use in applications such as optics, photonics, metameterials, and potentially a range of medical as well as sensing applications. This review will focus on key examples of the formation of such nano- and micro-filaments based on carbon nanofibers, polymers, synthetic oligo- and polypeptides, self-assembled organic molecules, and one prominent class of liquid crystals. The most critical aspects discussed here are the underlying driving forces for chiral filament formation, potentially answering why specific sizes and shapes are formed, what molecular design strategies are working equally well or rather differently among these materials classes, and what uses and applications are driving research in this fascinating field of materials science.
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Affiliation(s)
- Ashwathanarayana Gowda
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Suraj Kumar Pathak
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
| | - Grace A R Rohaley
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
| | - Gourab Acharjee
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Andrea Oprandi
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
| | - Ryan Williams
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
| | - Marianne E Prévôt
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Torsten Hegmann
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
- Brain Health Research Institute, Kent State University, Kent, OH 44242, USA
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2
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Sezgin B, Liu J, N. Gonçalves DP, Zhu C, Tilki T, Prévôt ME, Hegmann T. Controlling the Structure and Morphology of Organic Nanofilaments Using External Stimuli. ACS NANOSCIENCE AU 2023; 3:295-309. [PMID: 37601923 PMCID: PMC10436377 DOI: 10.1021/acsnanoscienceau.3c00005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 08/22/2023]
Abstract
In our continuing pursuit to generate, understand, and control the morphology of organic nanofilaments formed by molecules with a bent molecular shape, we here report on two bent-core molecules specifically designed to permit a phase or morphology change upon exposure to an applied electric field or irradiation with UV light. To trigger a response to an applied electric field, conformationally rigid chiral (S,S)-2,3-difluorooctyloxy side chains were introduced, and to cause a response to UV light, an azobenzene core was incorporated into one of the arms of the rigid bent core. The phase behavior as well as structure and morphology of the formed phases and nanofilaments were analyzed using differential scanning calorimetry, cross-polarized optical microscopy, circular dichroism spectropolarimetry, scanning and transmission electron microscopy, UV-vis spectrophotometry, as well as X-ray diffraction experiments. Both bent-core molecules were characterized by the coexistence of two nanoscale morphologies, specifically helical nanofilaments (HNFs) and layered nanocylinders, prior to exposure to an external stimulus and independent of the cooling rate from the isotropic liquid. The application of an electric field triggers the disappearance of crystalline nanofilaments and instead leads to the formation of a tilted smectic liquid crystal phase for the material featuring chiral difluorinated side chains, whereas irradiation with UV light results in the disappearance of the nanocylinders and the sole formation of HNFs for the azobenzene-containing material. Combined results of this experimental study reveal that in addition to controlling the rate of cooling, applied electric fields and UV irradiation can be used to expand the toolkit for structural and morphological control of suitably designed bent-core molecule-based structures at the nanoscale.
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Affiliation(s)
- Barış Sezgin
- Department
of Chemistry, Süleyman Demirel University, 32260 Isparta, Çünür, Turkey
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
| | - Jiao Liu
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
- Materials
Science Graduate Program, Kent State University, Kent, Ohio 44242 United States
| | - Diana P. N. Gonçalves
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
- Department
of Chemistry and Biochemistry, Kent State
University, Kent, Ohio 44242 United States
| | - Chenhui Zhu
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, Berkeley, California 94720 United States
| | - Tahir Tilki
- Department
of Chemistry, Süleyman Demirel University, 32260 Isparta, Çünür, Turkey
| | - Marianne E. Prévôt
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
| | - Torsten Hegmann
- Advanced
Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242 United States
- Materials
Science Graduate Program, Kent State University, Kent, Ohio 44242 United States
- Department
of Chemistry and Biochemistry, Kent State
University, Kent, Ohio 44242 United States
- Brain Health
Research Institute, Kent State University, Kent, Ohio 44242 United States
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3
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Liu J, Molard Y, Prévôt ME, Hegmann T. Highly Tunable Circularly Polarized Emission of an Aggregation-Induced Emission Dye Using Helical Nano- and Microfilaments as Supramolecular Chiral Templates. ACS APPLIED MATERIALS & INTERFACES 2022; 14:29398-29411. [PMID: 35713169 DOI: 10.1021/acsami.2c05012] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Aggregation-induced emission (AIE)-based circularly polarized luminescence (CPL) has been recognized as a promising pathway for developing chiroptical materials with high luminescence dissymmetry factors (|glum|). Here, we propose a method for the construction of a thermally tunable CPL-active system based on a supramolecular self-assembly approach that utilizes helical nano- or microfilament templates in conjunction with an AIE dye. The CPL properties of the ensuing ensembles are predominantly determined by the intrinsic geometric differences among the various filament templates such as their overall dimensions (width, height, and helical pitch) and the area fraction of the exposed aromatic segments or sublayers. The proposed mechanism is based on the collective data acquired by absorption, steady state and time-resolved fluorescence, absolute quantum yield, and CPL measurements. The highest |glum| value for the most promising dual-modulated helical nanofilament templates in the present series was further enhanced, reaching up to |glum| = 0.25 by confinement in the appropriate diameter of anodized aluminum oxide (AAO) nanochannels. It is envisioned that this methodology will afford new insights into the design of temperature-rate indicators or anti-counterfeiting tags using a combination of structural color by the nano- and microfilament templates and the AIE property of the guest dye.
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Affiliation(s)
- Jiao Liu
- Materials Science Graduate Program, Kent State University, Kent, Ohio 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Yann Molard
- Univ Rennes, ISCR - UMR 6226, ScanMAT - UAR 2025, F-35000 Rennes, France
| | - Marianne E Prévôt
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Torsten Hegmann
- Materials Science Graduate Program, Kent State University, Kent, Ohio 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
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4
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He C, Wang K, Wang Y, Xu S, Liu Y, Cao S. Properties tuning of supramolecular discotics by non-mesogenic triazines and acids. Aust J Chem 2022. [DOI: 10.1071/ch21189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Liu J, Shadpour S, Prévôt ME, Chirgwin M, Nemati A, Hegmann E, Lemieux RP, Hegmann T. Molecular Conformation of Bent-Core Molecules Affected by Chiral Side Chains Dictates Polymorphism and Chirality in Organic Nano- and Microfilaments. ACS NANO 2021; 15:7249-7270. [PMID: 33734664 DOI: 10.1021/acsnano.1c00527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The coupling between molecular conformation and chirality is a cornerstone in the construction of supramolecular helical structures of small molecules across various length scales. Inspired by biological systems, conformational preselection and control in artificial helical molecules, polymers, and aggregates has guided various applications in optics, photonics, and chiral sorting among others, which are frequently based on an inherent chirality amplification through processes such as templating and self-assembly. The so-called B4 nano- or microfilament phase formed by some bent-shaped molecules is an exemplary case for such chirality amplification across length scales, best illustrated by the formation of distinct nano- or microscopic chiral morphologies controlled by molecular conformation. Introduction of one or more chiral centers in the aliphatic side chains led to the discovery of homochiral helical nanofilament, helical microfilament, and heliconical-layered nanocylinder morphologies. Herein, we demonstrate how a priori calculations of the molecular conformation affected by chiral side chains are used to design bent-shaped molecules that self-assemble into chiral nano- and microfilament as well as nanocylinder conglomerates despite the homochiral nature of the molecules. Furthermore, relocation of the chiral center leads to formation of helical as well as flat nanoribbons. Self-consistent data sets from polarized optical as well as scanning and transmission electron microscopy, thin-film and solution circular dichroism spectropolarimetry, and synchrotron-based X-ray diffraction experiments support the progressive and predictable change in morphology controlled by structural changes in the chiral side chains. The formation of these morphologies is discussed in light of the diminishing effects of molecular chirality as the chain length increases or as the chiral center is moved away from the core-chain juncture. The type of phase (B1-columnar or B4) and morphology of the nano- or microfilaments generated can further be controlled by sample treatment conditions such as by the cooling rate from the isotropic melt or by the presence of an organic solvent in the ensuing colloidal dispersions. We show that these nanoscale morphologies can then organize into a wealth of two- and three-dimensional shapes and structures ranging from flower blossoms to fiber mats formed by intersecting flat nanoribbons.
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Affiliation(s)
- Jiao Liu
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Sasan Shadpour
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Marianne E Prévôt
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Michael Chirgwin
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Ahlam Nemati
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
| | - Elda Hegmann
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
- Department of Biological Sciences, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Robert P Lemieux
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Torsten Hegmann
- Materials Science Graduate Program, Kent State University, Kent (Ohio) 44242-0001, United States
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent (Ohio) 44242-0001, United States
- Department of Biological Sciences, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, United States
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6
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Park W, Yang M, Park H, Wolska JM, Ahn H, Shin TJ, Pociecha D, Gorecka E, Yoon DK. Directing Polymorphism in the Helical Nanofilament Phase. Chemistry 2021; 27:7108-7113. [PMID: 33464673 DOI: 10.1002/chem.202005221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/13/2021] [Indexed: 12/19/2022]
Abstract
Herein, it is reported that the polymorphism in the helical nanofilament (HNF, B4 ) liquid-crystalline phase depends on the fabrication methods, that is, UV-driven formation and template-assisted self-assembly in the nanoconfined geometry. As a result, uniaxially oriented HNFs with different helical structures were obtained, in which generation of the twisted-ribbon and cylindrical-ribbon polymorphs showed that even the molecular lattice has a different orientation. The detailed structures were directly observed by SEM and grazing-incidence X-ray diffraction with synchrotron radiation. The resultant polymorphs could be used in chiro-optical applications due to the capability for fine control of the helical structures.
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Affiliation(s)
- Wongi Park
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Minyong Yang
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Hyewon Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Joanna M Wolska
- Faculty of Chemistry, University of Warsaw, Warsaw, 02-089, Poland
| | - Hyungju Ahn
- Pohang Accelerator Laboratory, POSTECH, Pohang, 37673, Republic of Korea
| | - Tae Joo Shin
- UNIST Central Research Facilities & School of Natural Science, UNIST, Ulsan, 44919, Republic of Korea
| | - Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Warsaw, 02-089, Poland
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Warsaw, 02-089, Poland
| | - Dong Ki Yoon
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.,Department of Chemistry, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.,KAIST Institute for Nanocentury, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
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7
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Park W, Ha T, Jung TS, Sim KI, Kim JH, Wolska JM, Pociecha D, Gorecka E, Kim TT, Yoon DK. Security use of the chiral photonic film made of helical liquid crystal structures. NANOSCALE 2020; 12:21629-21634. [PMID: 32716441 DOI: 10.1039/d0nr03743e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The color change of photonic crystals (PCs) has been widely studied due to their beauty and anti-counterfeiting applications. Herein, we demonstrated security codes based on chiral PCs that cannot be easily mimicked and are quite different from the conventional technology used currently. The chiral PCs can be made by self-assembly and the structural colors change based on the polarization of the light in the transmission mode. These color changes are easily detected in real-time and are useful in the fabrication of anti-counterfeiting patterns that show beautiful and diverse color changes with rotating polarizers. We believe this can provide a new platform in various security and color-based applications.
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Affiliation(s)
- Wongi Park
- Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
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8
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Lewandowski W, Vaupotič N, Pociecha D, Górecka E, Liz-Marzán LM. Chirality of Liquid Crystals Formed from Achiral Molecules Revealed by Resonant X-Ray Scattering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1905591. [PMID: 32529663 DOI: 10.1002/adma.201905591] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 05/21/2023]
Abstract
Intensive research on chiral liquid crystals (LCs) has been fueled by their actively tunable physicochemical properties and structural complexity, comparable to those of sophisticated natural materials. Herein, recent progress in the discovery of new classes of chiral LCs, enabled by a combination of nano- and macroscale investigations is reviewed. First, an overview is provided of liquid crystalline phases, made of chiral and achiral low-weight molecules, that exhibit chiral structure and/or chiral morphology. Then, recent progress in the discovery of new classes of chiral LCs, particularly enabled by the application of resonant X-ray scattering is described. It is shown that the method is sensitive to modulations of molecular orientation and therefore provides information hardly accessible by means of other techniques, such as the sense of helical structures or chirality transfer across length scales. Finally, a perspective is presented on the future scope, opportunities, and challenges in the field of chiral LCs, in particular related to nanocomposites.
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Affiliation(s)
- Wiktor Lewandowski
- Faculty of Chemistry, University of Warsaw, Pasteura 1 St., Warsaw, 02-093, Poland
| | - Nataša Vaupotič
- Department of Physics, University of Maribor, Koroška 160, Maribor, 2000, Slovenia
- Jozef Stefan Institute, Jamova 39, Ljubljana, 1000, Slovenia
| | - Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Pasteura 1 St., Warsaw, 02-093, Poland
| | - Ewa Górecka
- Faculty of Chemistry, University of Warsaw, Pasteura 1 St., Warsaw, 02-093, Poland
| | - Luis M Liz-Marzán
- CIC biomaGUNE and CIBER-BBN, Paseo de Miramón 182, Donostia-San Sebastián, 20014, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48013, Spain
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9
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Orientation Control of Helical Nanofilament Phase and Its Chiroptical Applications. CRYSTALS 2020. [DOI: 10.3390/cryst10080675] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chiral liquid crystal phases show fascinating structural and optical properties due to their inherent helical characteristics. Among the various chiral liquid crystal phases, the helical nanofilament phase, made of achiral bent-shaped molecules, has been of keen research interest due to its unusual polar and chiral properties. This review is intended to introduce the recent progress in orientation control and its application to the helical nanofilament phase, which includes topographic confinement, photoalignment, and chiroptical applications such as photonic crystal and chirality sensor.
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10
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Shadpour S, Nemati A, Liu J, Hegmann T. Directing the Handedness of Helical Nanofilaments Confined in Nanochannels Using Axially Chiral Binaphthyl Dopants. ACS APPLIED MATERIALS & INTERFACES 2020; 12:13456-13463. [PMID: 32092259 DOI: 10.1021/acsami.9b20696] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In this work, we demonstrate control of the handedness of semicrystalline modulated helical nanofilaments (HNFmods) formed by achiral bent-core liquid crystal molecules by axially chiral binaphthyl-based additives as guest molecules solely under spatial nanoconfinement in anodic aluminum oxide nanochannels. The molecules of the same chiral additives are expelled from the HNFmods in the bulk, and as a result thereof do not affect the handedness or helical pitch of bulk HNFmods, resulting in an HNFmod conglomerate with chirality-preserving growth within each domain. However, under confinement these axially chiral guest molecules, likely embedded in the HNFmod host, do affect the helicity of the HNFmods. The configuration of the axially chiral molecules decides the HNFmod helix handedness and their concentration, and the helix angle is related to the helical pitch of the HNFmods. In addition to local imaging data obtained by scanning electron microscopy, global studies by thin-film circular dichroism spectropolarimetry support the imaging results.
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Affiliation(s)
- Sasan Shadpour
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Ahlam Nemati
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Jiao Liu
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
| | - Torsten Hegmann
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, Ohio 44242-0001, United States
- Department of Chemistry and Biochemistry, Kent State University, Kent, Ohio 44242-0001, United States
- Brain Health Research Institute, Kent State University, Kent, Ohio 44242-0001, United States
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11
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Shadpour S, Nemati A, Salamończyk M, Prévôt ME, Liu J, Boyd NJ, Wilson MR, Zhu C, Hegmann E, Jákli AI, Hegmann T. Missing Link between Helical Nano- and Microfilaments in B4 Phase Bent-Core Liquid Crystals, and Deciphering which Chiral Center Controls the Filament Handedness. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e1905591. [PMID: 31885139 DOI: 10.1002/smll.201905591] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/18/2019] [Indexed: 06/10/2023]
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 the para- and meta-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 featuring p2/m symmetry within the filaments and less pronounced crystalline character.
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Affiliation(s)
- Sasan Shadpour
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Ahlam Nemati
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | | | - Marianne E Prévôt
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Jiao Liu
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Nicola J Boyd
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK
| | - Mark R Wilson
- Department of Chemistry, Durham University, Durham, DH1 3LE, UK
| | - Chenhui Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Elda Hegmann
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
- Department of Biological Sciences, Kent State University, Kent, OH, 44242-0001, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Antal I Jákli
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
- Department of Physics and Astronomy, Kent State University, Kent, OH, 44242-0001, USA
| | - Torsten Hegmann
- Chemical Physics Interdisciplinary Program, Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
- Brain Health Research Institute, Kent State University, Kent, OH, 44242-0001, USA
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242-0001, USA
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12
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Murachver MT, Nemati A, Salamończyk M, Bullock C, Sabata Z, Rahmani H, Vorobiova T, Izadnegahdar A, Salili SM, Norman V, Zhu C, Hegmann T, Sprunt SN, Gleeson JT, Jakli AI. Indication of a twist-grain-boundary-twist-bend phase of flexible core bent-shape chiral dimers. SOFT MATTER 2019; 15:3283-3290. [PMID: 30931469 DOI: 10.1039/c8sm02338g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The effect of the molecular chirality of chiral additives on the nanostructure of the twist-bend nematic (NTB) liquid crystal phase with ambidextrous chirality and nanoscale pitch due to spontaneous symmetry breaking is studied. It is found that the ambidextrous nanoscale pitch of the NTB phase increases by 50% due to 3% chiral additive, and the chiral transfer among the biphenyl groups disappears in the NTB* phase. Most significantly, a twist-grain boundary (TGB) type phase is found at c > 1.5 wt% chiral additive concentrations below the usual N* phase and above the non-CD active NTB* phase. In such a TGB type phase, the adjacent blocks of pseudo-layers of the nanoscale pitch rotate across the grain boundaries.
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Affiliation(s)
- Matthew T Murachver
- Chemical Physics Interdisciplinary Program & Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
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13
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Abstract
Polymorphism is a remarkable concept in chemistry, materials science, computer science, and biology. Whether it is the ability of a material to exist in two or more crystal structures, a single interface connecting to two different entities, or alternative phenotypes of an organism, polymorphism determines function and properties. In materials science, polymorphism can be found in an impressively wide range of materials, including crystalline materials, minerals, metals, alloys, and polymers. Here we report on polymorphism in a liquid crystal. A bent-core liquid crystal with a single chiral side chain forms two structurally and morphologically significantly different liquid crystal phases solely depending on the cooling rate from the isotropic liquid state. On slow cooling, the thermodynamically more stable oblique columnar phase forms, and on rapid cooling, a not heretofore reported helical microfilament phase. Since structure determines function and properties, the structural color for these phases also differs.
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14
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Kim DY, Lee SA, Kim S, Nah C, Lee SH, Jeong KU. Asymmetric Fullerene Nanosurfactant: Interface Engineering for Automatic Molecular Alignments. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:1702439. [PMID: 29134757 DOI: 10.1002/smll.201702439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 08/20/2017] [Indexed: 06/07/2023]
Abstract
Since the molecular self-assembly of nanomaterials is sensitive to their surface properties, the molecular packing structure on the surface is essential to build the desired chemical and physical properties of nanomaterials. Here, a new nanosurfactant is proposed for the automatic construction of macroscopic surface alignment layer for liquid crystal (LC) molecules. An asymmetric nanosurfactant (C60 NS) consisted of mesogenic cyanobiphenyl moieties with flexible alkyl chains and a [60]fullerene nanoatom is newly designed and precisely synthesized. The C60 NS directly introduced in the anisotropic LC medium is self-assembled into the monolayered protrusions on the surface because of its amphiphilic nature originated by asymmetrically programmed structural motif of LC-favoring moieties and LC-repelling groups. The monolayered protrusions constructed by the phase-separation and self-assembly of asymmetric C60 NS nanosurfactant in the anisotropic LC media amplify and transfer the molecular orientational order from surface to bulk, and finally create the automatic vertical molecular alignment on the macroscopic length scale. The asymmetric C60 NS nanosurfactant and its self-assembly described herein can offer the direct guideline of interface engineering for the automatic molecular alignments.
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Affiliation(s)
- Dae-Yoon Kim
- BK21 Plus Haptic Polymer Composite Research Team & Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, 54896, South Korea
| | - Sang-A Lee
- BK21 Plus Haptic Polymer Composite Research Team & Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, 54896, South Korea
| | - Soeun Kim
- BK21 Plus Haptic Polymer Composite Research Team & Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, 54896, South Korea
| | - Changwoon Nah
- BK21 Plus Haptic Polymer Composite Research Team & Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, 54896, South Korea
| | - Seung Hee Lee
- Department of BIN Convergence Technology, Chonbuk National University, Jeonju, 54896, South Korea
| | - Kwang-Un Jeong
- BK21 Plus Haptic Polymer Composite Research Team & Department of Polymer-Nano Science and Technology, Chonbuk National University, Jeonju, 54896, South Korea
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15
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Shi Y, Sun Z, Chen R, Zhu C, Shoemaker RK, Tsai E, Walba DM, Glaser MA, Maclennan JE, Chen D, Clark NA. Effect of Conformational Chirality on Optical Activity Observed in a Smectic of Achiral, Bent-Core Molecules. J Phys Chem B 2017; 121:6944-6950. [DOI: 10.1021/acs.jpcb.7b04033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yue Shi
- State
Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, United States
| | - Zeyong Sun
- State
Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
- Institute
of Process Equipment, College of Energy Engineering, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
| | - Ran Chen
- State
Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
- Institute
of Process Equipment, College of Energy Engineering, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
| | - Chenhui Zhu
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, United States
| | - Richard K. Shoemaker
- Department
of Chemistry and Biochemistry and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Ethan Tsai
- Department
of Chemistry and Biochemistry and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0215, United States
- Department
of Chemistry, Metropolitan State University of Denver, Denver, Colorado 80217, United States
| | - David M. Walba
- Department
of Chemistry and Biochemistry and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0215, United States
| | - Matthew A. Glaser
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, United States
| | - Joseph E. Maclennan
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, United States
| | - Dong Chen
- State
Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, United States
- Institute
of Process Equipment, College of Energy Engineering, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
| | - Noel A. Clark
- Department
of Physics and Soft Materials Research Center, University of Colorado, Boulder, Colorado 80309-0390, United States
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