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Gibb CJ, Hobbs J, Nikolova DI, Raistrick T, Berrow SR, Mertelj A, Osterman N, Sebastián N, Gleeson HF, Mandle RJ. Spontaneous symmetry breaking in polar fluids. Nat Commun 2024; 15:5845. [PMID: 38992039 PMCID: PMC11239904 DOI: 10.1038/s41467-024-50230-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 07/03/2024] [Indexed: 07/13/2024] Open
Abstract
Spontaneous symmetry breaking and emergent polar order are each of fundamental importance to a range of scientific disciplines, as well as generating rich phase behaviour in liquid crystals (LCs). Here, we show the union of these phenomena to lead to two previously undiscovered polar liquid states of matter. Both phases have a lamellar structure with an inherent polar ordering of their constituent molecules. The first of these phases is characterised by polar order and a local tilted structure; the tilt direction processes about a helix orthogonal to the layer normal, the period of which is such that we observe selective reflection of light. The second new phase type is anti-ferroelectric, with the constituent molecules aligning orthogonally to the layer normal. This has led us to term the phases the Sm C P H and SmAAF phases, respectively. Further to this, we obtain room temperature ferroelectric nematic (NF) and Sm C P H phases via binary mixture formulation of the novel materials described here with a standard NF compound (DIO), with the resultant materials having melting points (and/or glass transitions) which are significantly below ambient temperature. The new soft matter phase types discovered herein can be considered as electrical analogues of topological structures of magnetic spins in hard matter.
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Affiliation(s)
- Calum J Gibb
- School of Chemistry, University of Leeds, Leeds, UK
| | - Jordan Hobbs
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | | | | | - Stuart R Berrow
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | | | - Natan Osterman
- Jožef Stefan Institute, Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
| | | | - Helen F Gleeson
- School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Richard J Mandle
- School of Chemistry, University of Leeds, Leeds, UK.
- School of Physics and Astronomy, University of Leeds, Leeds, UK.
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2
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Hockey-Stick Polycatenars: Network formation and transition from one dimensional to three-dimensional liquid crystalline phases. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.118613] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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3
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Nematic ordering of model racemic mixture of stiff trimer chains. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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4
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Zhao K, Xiao Y, Chang Q, Zhang D, Cheng X. Azobenzene-based asymmetric bolaamphiphiles: Formation of LC phases with honeycomb structures and gels with helical structures. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111417] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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5
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Wu Q, Soluyanov AA, Bzdušek T. Non-Abelian band topology in noninteracting metals. Science 2019; 365:1273-1277. [DOI: 10.1126/science.aau8740] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 08/14/2019] [Indexed: 01/25/2023]
Affiliation(s)
- QuanSheng Wu
- Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
- National Centre for Computational Design and Discovery of Novel Materials MARVEL, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Alexey A. Soluyanov
- Physik-Institut, Universität Zürich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
- Department of Physics, St. Petersburg State University, St. Petersburg, 199034 Russia
| | - Tomáš Bzdušek
- Department of Physics, McCullough Building, Stanford University, Stanford, CA 94305, USA
- Stanford Center for Topological Quantum Physics, Stanford University, Stanford, CA 94305, USA
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6
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Eichler JC, Skutnik RA, Sengupta A, Mazza MG, Schoen M. Emergent biaxiality in nematic microflows illuminated by a laser beam. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1663286] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Jan-Christoph Eichler
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Berlin, Germany
| | - Robert A. Skutnik
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Berlin, Germany
| | - Anupam Sengupta
- Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg City, Grand Duchy of Luxembourg
| | - Marco G. Mazza
- Interdisciplinary Centre for Mathematical Modelling and Department of Mathematical Sciences, Loughborough University, Loughborough, UK
- Max Planck Institute for Dynamics and Self-Organization (MPIDS), Göttingen, Germany
| | - Martin Schoen
- Stranski-Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Berlin, Germany
- Department of Chemical Engineering, Imperial College London, London, UK
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7
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Liu J, Guan R, Dong X, Dong Y. Molecular properties of a bent-core nematic liquid crystal A131 by multi-level theory simulations. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1517416] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Jingwei Liu
- Jilin Provincial Key Laboratory for Numerical Simulation, Jilin Normal University, Siping, People’s Republic of China
| | - Rongfeng Guan
- College of Applied Chemistry, Shenyang University of Chemical Technology, Shenyang, People’s Republic of China
| | - Xuanchen Dong
- College of Chemistry, Jilin University, Changchun, People’s Republic of China
| | - Yanhua Dong
- Jilin Provincial Key Laboratory for Numerical Simulation, Jilin Normal University, Siping, People’s Republic of China
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8
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Yu M, Jiang Y, Shin Y, Jiang J, Yang H, Zhang H, Xue J, Li Q, Yang DK. Effect of biaxiality on chirality in chiral nematic liquid crystals. SOFT MATTER 2018; 14:6530-6536. [PMID: 30051126 DOI: 10.1039/c8sm00898a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Biaxiality and chirality are two of the most interesting topics in materials and biological science, particularly in liquid crystals. What is even more interesting is that these two properties are related. It was theoretically predicted that morphological chirality is impossible without morphological biaxiality in chiral nematic liquid crystals. We experimentally study the effect of biaxiality on chirality. We show that when achiral liquid crystal dimers with large molecular biaxiality are doped into chiral nematic liquid crystals, their helical pitch is significantly decreased. We have also observed an abnormal fingerprint texture of the chiral nematic liquid crystal doped dimers, which suggests morphological biaxiality. Our experimental results support the biaxial theory of chiral nematic liquid crystals.
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Affiliation(s)
- Meina Yu
- Chemical Physics Interdisciplinary Program and Liquid Crystal Institute, Kent State University, Kent, OH 44242, USA.
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9
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Kumar J, Prasad V. Ferroelectric Nematic and Ferrielectric Smectic Mesophases in an Achiral Bent-Core Azo Compound. J Phys Chem B 2018; 122:2998-3007. [PMID: 29485879 DOI: 10.1021/acs.jpcb.7b11733] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Here, we report the observation of ferroelectric nematic and ferrielectric smectic mesophases in an achiral bent-core azo compound consisting of nonsymmetrical molecules with a lateral fluoro substitution on one of the wings. These mesophases are enantiotropic in nature with fairly low transition temperatures and wide mesophase ranges. The liquid crystalline properties of this compound are investigated using polarizing optical microscope, differential scanning calorimeter, X-ray diffraction, and electro-optical studies. As revealed by X-ray diffraction measurements, the nematic mesophase is composed of skewed cybotactic clusters and, in the smectic mesophase, the molecules are tilted with respect to the layer normal. The polar order in these mesophases was confirmed by the electro-optical switching and dielectric spectroscopy measurements. The dielectric study in the nematic mesophase shows a single relaxation process at low frequency ( f < 1 kHz) measured in the range 10 Hz to 5 MHz, which is attributed to the collective motion of the molecules within cybotactic clusters. The formation of local polar order in these clusters leads to a ferroelectric-like polar switching in the nematic mesophase. Of particular interest is the fact that the smectic phase exhibits a field induced ferrielectric state, which can be exploited for designing of the potential optical devices due to multistate switching.
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Affiliation(s)
- Jitendra Kumar
- Centre for Nano and Soft Matter Sciences , P.B. No. 1329, Jalahalli, Bengaluru - 560 013 , India
| | - Veena Prasad
- Centre for Nano and Soft Matter Sciences , P.B. No. 1329, Jalahalli, Bengaluru - 560 013 , India
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10
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Vaghela A, Teixeira PIC, Terentjev EM. Emergence of biaxial nematic phases in solutions of semiflexible dimers. Phys Rev E 2018; 96:042703. [PMID: 29347574 DOI: 10.1103/physreve.96.042703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Indexed: 11/07/2022]
Abstract
We investigate the isotropic, uniaxial nematic and biaxial nematic phases, and the transitions between them, for a model lyotropic mixture of flexible molecules consisting of two rigid rods connected by a spacer with variable bending stiffness. We apply density-functional theory within the Onsager approximation to describe strictly excluded-volume interactions in this athermal model and to self-consistently find the orientational order parameters dictated by its complex symmetry, as functions of the density. Earlier work on lyotropic ordering of rigid bent-rod molecules is reproduced and extended to show explicitly the continuous phase transition at the Landau point, at a critical bend angle of 36^{∘}. For flexible dimers with no intrinsic biaxiality, we find that a biaxial nematic phase can nevertheless form at a sufficiently high density and low bending stiffness. For bending stiffness κ>0.86k_{B}T, this biaxial phase manifests as dimer bending fluctuations occurring preferentially in one plane. When the dimers are more flexible, κ<0.86k_{B}T, the modal shape of the fluctuating dimer is a V with an acute opening angle, and one of the biaxial order parameters changes sign, indicating a rotation of the directors. These two regions are separated by a narrow strip of uniaxial nematic in the phase diagram, which we generate in terms of the spacer stiffness and particle density.
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Affiliation(s)
- Arvin Vaghela
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
| | - Paulo I C Teixeira
- ISEL-Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa Rua Conselheiro Emídio Navarro 1, 1959-007 Lisbon, Portugal.,Centro de Física Teórica e Computacional Faculdade de Ciências da Universidade de Lisboa Campo Grande, Edifício C8, 1749-016 Lisbon, Portugal
| | - Eugene M Terentjev
- Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom
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11
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Unsymmetrical achiral four ring hockey stick shaped mesogens based on 1,3,4-oxadiazole: Photophysical, mesogenic and DFT studies. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.06.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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12
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Aliev MA, Kuzminyh NY, Ugolkova EA. Phase behavior of the thermotropic melt of asymmetric V-shaped molecules. Phys Rev E 2017; 95:042703. [PMID: 28505871 DOI: 10.1103/physreve.95.042703] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Indexed: 11/07/2022]
Abstract
The phase behavior of the monodisperse melt of V-shaped molecules composed of two rigid segments of different lengths joined at their ends at an external angle α has been examined within the Landau-de Gennes approach. Each rigid segment consists of a sequence of monomer units; the anisotropic interactions in the system are assumed to be of the Maier-Saupe form. The coefficients of the Landau-de Gennes free-energy expansion have been found from a microscopic model of V-shaped molecule. A single Landau point at which the system undergoes direct continuous transition from isotropic to biaxial nematic phase is found for asymmetry parameter ϕ=1/3 or ϕ=2/3, where ϕ is the number fraction of monomer units in one of the segments. Two Landau points are found in a range 1/3<ϕ<2/3. Only isotropic and nematic states are found to be stable for 0≤ϕ<1/3 and 2/3<ϕ≤1. Regions of stability of isotropic, prolate uniaxial, and biaxial nematic phases are found for ϕ=1/3 and ϕ=2/3. In addition, a stable oblate uniaxial phase is revealed if asymmetry parameter falls in the range 1/3<ϕ<2/3. The region of stability of the biaxial nematic phase becomes smaller as parameter ϕ increases from 1/3 to 1/2 (or decreases from 2/3 to 1/2). Coefficients of the gradient terms have been found; for certain values of asymmetry parameter these coefficients can become negative in some ranges of angles.
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Affiliation(s)
- M A Aliev
- Institute of Biochemical Physics, 4, Kosygina Str., 119334, Moscow, Russia
| | - N Yu Kuzminyh
- Institute of Biochemical Physics, 4, Kosygina Str., 119334, Moscow, Russia
| | - E A Ugolkova
- Institute of General and Inorganic Chemistry, 31 Leninsky pr., 119991, Moscow, Russia
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13
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Kishikawa K, Yamamoto Y, Watanabe G, Kawamura A, Kohri M, Taniguchi T. Shape-Assisted Self-Organization in Highly Disordered Liquid Crystal Phases. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201700809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Keiki Kishikawa
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Yusuke Yamamoto
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Go Watanabe
- Department of Physics; School of Science; Kitasato University; 1-15-1 Kitasato, Minami-ku, Sagamihara Kanagawa 252-0373 Japan
| | - Ayaka Kawamura
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Michinari Kohri
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Tatsuo Taniguchi
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
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14
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Kishikawa K, Yamamoto Y, Watanabe G, Kawamura A, Kohri M, Taniguchi T. Shape-Assisted Self-Organization in Highly Disordered Liquid Crystal Phases. Angew Chem Int Ed Engl 2017; 56:4598-4602. [DOI: 10.1002/anie.201700809] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/23/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Keiki Kishikawa
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Yusuke Yamamoto
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Go Watanabe
- Department of Physics; School of Science; Kitasato University; 1-15-1 Kitasato, Minami-ku, Sagamihara Kanagawa 252-0373 Japan
| | - Ayaka Kawamura
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Michinari Kohri
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
| | - Tatsuo Taniguchi
- Department of Applied Chemistry and Biotechnology; Graduate School of Engineering; Chiba University; 1-33 Yayoi-cho, Inage-ku Chiba 263-8522 Japan
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15
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M. M, Roy A, Prasad V. Smectic nanoclusters in the nematic mesophases of dimeric compounds composed of rod-like azo moieties with lateral substituents. NEW J CHEM 2017. [DOI: 10.1039/c7nj00870h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photochromic liquid crystalline dimers that form smectic nanoclusters in nematic mesophases and are capable of forming organogels have been reported.
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Affiliation(s)
- Monika M.
- Centre for Nano and Soft Matter Sciences
- Bengaluru – 560 013
- India
| | - Arun Roy
- Raman Research Institute
- Bengaluru – 560 080
- India
| | - Veena Prasad
- Centre for Nano and Soft Matter Sciences
- Bengaluru – 560 013
- India
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16
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Arakawa Y, Sasaki Y, Igawa K, Tsuji H. Hydrogen bonding liquid crystalline benzoic acids with alkylthio groups: phase transition behavior and insights into the cybotactic nematic phase. NEW J CHEM 2017. [DOI: 10.1039/c7nj00282c] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel class of hydrogen bonding liquid crystalline benzoic acids with alkylthio groups was established and their phase transition behavior was investigated in detail.
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Affiliation(s)
- Yuki Arakawa
- Department of Environmental and Life Sciences
- Graduate School of Engineering
- Toyohashi University of Technology
- Toyohashi
- Japan
| | - Yukito Sasaki
- Department of Environmental and Life Sciences
- Graduate School of Engineering
- Toyohashi University of Technology
- Toyohashi
- Japan
| | - Kazunobu Igawa
- Institute for Materials Chemistry and Engineering
- Kyushu University
- Fukuoka 816-8580
- Japan
| | - Hideto Tsuji
- Department of Environmental and Life Sciences
- Graduate School of Engineering
- Toyohashi University of Technology
- Toyohashi
- Japan
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17
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Kang S, Lee EW, Li T, Liang X, Tokita M, Nakajima K, Watanabe J. Two-Dimensional Skyrmion Lattice Formation in a Nematic Liquid Crystal Consisting of Highly Bent Banana Molecules. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201606388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Sungmin Kang
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Eun-Woo Lee
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Tianqi Li
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Xiaobin Liang
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Masatoshi Tokita
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Ken Nakajima
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Junji Watanabe
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
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18
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Kang S, Lee EW, Li T, Liang X, Tokita M, Nakajima K, Watanabe J. Two-Dimensional Skyrmion Lattice Formation in a Nematic Liquid Crystal Consisting of Highly Bent Banana Molecules. Angew Chem Int Ed Engl 2016; 55:11552-6. [DOI: 10.1002/anie.201606388] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Sungmin Kang
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Eun-Woo Lee
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Tianqi Li
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Xiaobin Liang
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Masatoshi Tokita
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Ken Nakajima
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
| | - Junji Watanabe
- Department of Chemical Science and Engineering; School of Materials and Chemical Technology; Tokyo Institute of Technology; 2-12-1 O-okayama Tokyo 152-8552 Japan
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19
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Alaasar M, Prehm M, Tschierske C. Helical Nano-crystallite (HNC) Phases: Chirality Synchronization of Achiral Bent-Core Mesogens in a New Type of Dark Conglomerates. Chemistry 2016; 22:6583-97. [DOI: 10.1002/chem.201505016] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Mohamed Alaasar
- Institute of Chemistry; Martin Luther University Halle-Wittenberg; Kurt Mothes Str. 2 06120 Halle (Saale) Germany), Fax
- Department of Chemistry; Faculty of Science; Cairo University; Giza Egypt
| | - Marko Prehm
- Institute of Chemistry; Martin Luther University Halle-Wittenberg; Kurt Mothes Str. 2 06120 Halle (Saale) Germany), Fax
| | - Carsten Tschierske
- Institute of Chemistry; Martin Luther University Halle-Wittenberg; Kurt Mothes Str. 2 06120 Halle (Saale) Germany), Fax
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20
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Ritos K, Borg MK, Mottram NJ, Reese JM. Electric fields can control the transport of water in carbon nanotubes. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2016; 374:rsta.2015.0025. [PMID: 26712640 PMCID: PMC4696074 DOI: 10.1098/rsta.2015.0025] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/12/2015] [Indexed: 06/05/2023]
Abstract
The properties of water confined inside nanotubes are of considerable scientific and technological interest. We use molecular dynamics to investigate the structure and average orientation of water flowing within a carbon nanotube. We find that water exhibits biaxial paranematic liquid crystal ordering both within the nanotube and close to its ends. This preferred molecular ordering is enhanced when an axial electric field is applied, affecting the water flow rate through the nanotube. A spatially patterned electric field can minimize nanotube entrance effects and significantly increase the flow rate.
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Affiliation(s)
- Konstantinos Ritos
- Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ, UK
| | - Matthew K Borg
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, UK
| | - Nigel J Mottram
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow G1 1XH, UK
| | - Jason M Reese
- School of Engineering, University of Edinburgh, Edinburgh EH9 3FB, UK
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21
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Piccionello AP, Calabrese A, Pibiri I, Giacalone V, Pace A, Buscemi S. Synthesis of Fluorinated Bent-Core Mesogens (BCMs) Containing the 1,2,4-Oxadiazole Ring. J Heterocycl Chem 2015. [DOI: 10.1002/jhet.2509] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Antonio Palumbo Piccionello
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche; Università di Palermo; Viale delle Scienze, ed. 17 90128 Palermo Italy
- Istituto Euro-mediterraneo di scienza e Tecnologia, IEMEST; Via E. Amari 123 90145 Palermo Italy
| | - Alessandro Calabrese
- ENEA UTTRI-Ufficio territoriale della Sicilia-via Principe di Granatelli 24; 90139 Palermo Italy
| | - Ivana Pibiri
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche; Università di Palermo; Viale delle Scienze, ed. 17 90128 Palermo Italy
- Istituto Euro-mediterraneo di scienza e Tecnologia, IEMEST; Via E. Amari 123 90145 Palermo Italy
| | - Valentina Giacalone
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche; Università di Palermo; Viale delle Scienze, ed. 17 90128 Palermo Italy
| | - Andrea Pace
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche; Università di Palermo; Viale delle Scienze, ed. 17 90128 Palermo Italy
- Istituto Euro-mediterraneo di scienza e Tecnologia, IEMEST; Via E. Amari 123 90145 Palermo Italy
| | - Silvestre Buscemi
- Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche; Università di Palermo; Viale delle Scienze, ed. 17 90128 Palermo Italy
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22
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Kim YK, Cukrov G, Xiang J, Shin ST, Lavrentovich OD. Domain walls and anchoring transitions mimicking nematic biaxiality in the oxadiazole bent-core liquid crystal C7. SOFT MATTER 2015; 11:3963-3970. [PMID: 25820380 DOI: 10.1039/c5sm00580a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We investigate the origin of "secondary disclinations" that were recently described as new evidence of a biaxial nematic phase in an oxadiazole bent-core thermotropic liquid crystal C7. Using an assortment of optical techniques such as polarizing optical microscopy, LC PolScope, and fluorescence confocal polarizing microscopy, we demonstrate that the secondary disclinations represent non-singular domain walls formed in a uniaxial nematic phase during the surface anchoring transition, in which surface orientation of the director changes from tangential (parallel to the bounding plates) to tilted. Each domain wall separates two regions with the director tilted in opposite azimuthal directions. At the centre of the wall, the director remains parallel to the bounding plates. The domain walls can be easily removed by applying a moderate electric field. The anchoring transition is explained by the balance of (a) the intrinsic perpendicular surface anchoring produced by the polyimide aligning layer and (b) tangential alignment caused by ionic impurities forming electric double layers. The model is supported by the fact that the temperature of the tangentially tilted anchoring transition decreases as the cell thickness increases and as the concentration of ionic species (added salt) increases. We also demonstrate that the surface alignment is strongly affected by thermal degradation of the samples. This study shows that C7 exhibits only a uniaxial nematic phase and demonstrates yet another mechanism (formation of "secondary disclinations") by which a uniaxial nematic phase can mimic a biaxial nematic behaviour.
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Affiliation(s)
- Young-Ki Kim
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA.
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23
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González-Pinto M, Martínez-Ratón Y, Velasco E, Varga S. Effect of shape biaxiality on the phase behavior of colloidal liquid-crystal monolayers. Phys Chem Chem Phys 2015; 17:6389-400. [PMID: 25655742 DOI: 10.1039/c4cp04812a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We extend our previous work on monolayers of uniaxial particles [J. Chem. Phys., 2014, 140, 204906] to study the effect of particle biaxiality on the phase behavior of liquid-crystal monolayers. Particles are modelled as board-like hard bodies with three different edge lengths σ1 ≥ σ2 ≥ σ3, and the restricted-orientation approximation (Zwanzig model) is used. A density-functional formalism based on the fundamental-measure theory is used to calculate phase diagrams for a wide range of values with the largest aspect ratio κ1 = σ1/σ3 ∈ [1,100]. We find that particle biaxiality in general destabilizes the biaxial nematic phase already present in monolayers of uniaxial particles. While plate-like particles exhibit strong biaxial ordering, rod-like ones with κ1 > 21.34 exhibit reentrant uniaxial and biaxial phases. As particle geometry is changed from uniaxial- to increasingly biaxial-rod-like, the region of biaxiality is reduced, eventually ending in a critical-end point. For κ1 > 60, a density gap opens up in which the biaxial nematic phase is stable for any particle biaxiality. Regions of the phase diagram, where packing-fraction inversion occurs (i.e. packing fraction is a decreasing function of density), are found. Our results are compared with the recent experimental studies on nematic phases of magnetic nanorods.
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Affiliation(s)
- Miguel González-Pinto
- Departamento de Física Teórica de la Materia Condensada, Facultad de Ciencias, Universidad Autónoma de Madrid, E-28049 Madrid, Spain.
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24
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Figueirinhas JL, Dong RY. NMR of bent-core nematogens: a mini-review. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2014; 52:614-624. [PMID: 24975632 DOI: 10.1002/mrc.4097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/26/2014] [Indexed: 06/03/2023]
Abstract
This review focuses on two of our studied bent-core liquid crystals 2-methyl-3-[4-(4-octylbenzoyloxy)-benzylidene]-amino-benzoic acid 4-(4-dodecylphenylazo)-phenyl ester A131, and a shape-persistent fluorenone mesogen, F1a by means of temperature-dependent (13)C NMR spectra and deuterium NMR spectra, respectively. Orientational order parameters, molecular packing, and/or conformations in the nematic phases or nematic glass can be extracted from the observed NMR spectra. These will be discussed in terms of certain motional models. In particular, F1a has been found to form a biaxial nematic glass. The derived orientational order parameters would put the biaxial system of phase symmetry lower than orthorhombic.
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Affiliation(s)
- João L Figueirinhas
- Departamento de Física, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal; CFMC, Universidade de Lisboa, Lisboa, Portugal
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25
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Choi EJ, Seo YH, Kamal T, Park SY, Watanabe J. Cybotactic nematic phase in main-chain polyesters with bent-core mesogens. POLYMER 2014. [DOI: 10.1016/j.polymer.2014.02.050] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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26
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Rieth T, Marszalek T, Pisula W, Detert H. Thermotropic Properties and Molecular Packing of Discotic Tristriazolotriazines with Rigid Substituents. Chemistry 2014; 20:5000-6. [DOI: 10.1002/chem.201400034] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Indexed: 11/06/2022]
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27
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Greco C, Marini A, Frezza E, Ferrarini A. From the Molecular Structure to Spectroscopic and Material Properties: Computational Investigation of a Bent-Core Nematic Liquid Crystal. Chemphyschem 2014; 15:1336-44. [DOI: 10.1002/cphc.201301030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Indexed: 11/12/2022]
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28
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Kim YK, Senyuk B, Shin ST, Kohlmeier A, Mehl GH, Lavrentovich OD. Surface alignment, anchoring transitions, optical properties, and topological defects in the thermotropic nematic phase of organo-siloxane tetrapodes. SOFT MATTER 2014; 10:500-509. [PMID: 24651889 DOI: 10.1039/c3sm52249k] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We perform optical, surface anchoring, and textural studies of an organo-siloxane "tetrapode" material in the broad temperature range of the nematic phase. The optical, structural, and topological features are compatible with the uniaxial nematic order rather than with the biaxial nematic order, in the entire nematic temperature range -25 °C < T < 46 °C studied. For homeotropic alignment, the material experiences surface anchoring transition, but the director can be realigned into an optically uniaxial texture by applying a sufficiently strong electric field. The topological features of textures in cylindrical capillaries, in spherical droplets and around colloidal inclusions are consistent with the uniaxial character of the long-range nematic order. In particular, we observe isolated surface point defects - boojums and bulk point defects - hedgehogs that can exist only in the uniaxial nematic liquid crystal.
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Affiliation(s)
- Young-Ki Kim
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent, OH 44242, USA.
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29
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Gimeno N, Pintre I, Martínez-Abadía M, Serrano JL, Ros MB. Bent-core liquid crystal phases promoted by azo-containing molecules: from monomers to side-chain polymers. RSC Adv 2014. [DOI: 10.1039/c4ra02079k] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In situ photopolymerization or ATRP in solution provide azo-containing polymers showing room temperature SmCPg arrangements and broad ranges of SmCP mesophase.
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Affiliation(s)
- Nélida Gimeno
- Instituto de Ciencia de Materiales de Aragón
- Universidad de Zaragoza-CSIC
- Departamento de Química Orgánica
- Facultad de Ciencias
- 50009 Zaragoza, Spain
| | - Inmaculada Pintre
- Instituto de Ciencia de Materiales de Aragón
- Universidad de Zaragoza-CSIC
- Departamento de Química Orgánica
- Facultad de Ciencias
- 50009 Zaragoza, Spain
| | - Marta Martínez-Abadía
- Instituto de Ciencia de Materiales de Aragón
- Universidad de Zaragoza-CSIC
- Departamento de Química Orgánica
- Facultad de Ciencias
- 50009 Zaragoza, Spain
| | - José Luis Serrano
- Instituto de Nanociencia de Aragón
- Universidad de Zaragoza
- Departamento de Química Orgánica
- Facultad de Ciencias
- 50009 Zaragoza, Spain
| | - M. Blanca Ros
- Instituto de Ciencia de Materiales de Aragón
- Universidad de Zaragoza-CSIC
- Departamento de Química Orgánica
- Facultad de Ciencias
- 50009 Zaragoza, Spain
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30
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Paul MK, Kalita G, Laskar AR, Debnath S, Gude V, Sarkar DD, Mohiuddin G, Varshney SK, Nandiraju Rao V. Synthesis and mesomorphic behaviour of achiral four-ring unsymmetrical bent-core liquid crystals: Nematic phases. J Mol Struct 2013. [DOI: 10.1016/j.molstruc.2013.06.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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31
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Alaasar M, Prehm M, Nagaraj M, Vij JK, Tschierske C. A liquid crystalline phase with uniform tilt, local polar order and capability of symmetry breaking. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2013; 25:2186-2191. [PMID: 23427137 DOI: 10.1002/adma.201205180] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Indexed: 06/01/2023]
Abstract
A new liquid crystalline (LC) phase with uniform tilt, local polar order and capability of symmetry breaking is found for a bent-core mesogen combining a 4-cyanoresorcinol unit with two azobenzene wings. The combination of local polar order and long range synclinic tilt in this SmC(s)P(R) phase leads, under special conditions, to macroscopic domains with opposite chirality, though the molecules themselves are achiral.
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Affiliation(s)
- Mohamed Alaasar
- Department of Chemistry, Faculty of Science, Cairo University, Giza, Egypt.
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32
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Srinivasan MV, Kannan P, Roy A. Photo and electrically switchable behavior of azobenzene containing pendant bent‐core liquid crystalline polymers. ACTA ACUST UNITED AC 2012. [DOI: 10.1002/pola.26455] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
| | - P. Kannan
- Department of Chemistry, Anna University, Chennai, India
| | - A. Roy
- Soft Condensed Matter, Raman Research Institute, Bangaluru, India
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33
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Aluculesei A, Vaca Chávez F, Cruz C, Sebastião PJ, Nagaveni NG, Prasad V, Dong RY. Proton NMR Relaxation Study on the Nematic–Nematic Phase Transition in A131 Liquid Crystal. J Phys Chem B 2012; 116:9556-63. [DOI: 10.1021/jp305064x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- A Aluculesei
- Department of Physics, Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal
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34
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Chen HH, Lin HA, Lai YH, Lin SY, Chiang CH, Hsu HF, Shih TL, Lee JJ, Lai CC, Kuo TS. Enantiotropic Nematics From Cross-Like 1,2,4,5-Tetrakis(4′-alkyl-4-ethynylbiphenyl)benzenes and Their Biaxiality Studies. Chemistry 2012; 18:9543-51. [DOI: 10.1002/chem.201103453] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 04/14/2012] [Indexed: 11/07/2022]
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35
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Nagaveni NG, Roy A, Prasad V. Achiral bent-core azo compounds: effect of different types of linkage groups and their direction of linking on liquid crystalline properties. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm30709j] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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36
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Gim MJ, Hur ST, Park KW, Lee M, Choi SW, Takezoe H. Photoisomerization-induced stable liquid crystalline cubic blue phase. Chem Commun (Camb) 2012; 48:9968-70. [DOI: 10.1039/c2cc34114j] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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37
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Benzie PW, Corbett D, Elston SJ. Simulation of the viewing properties and optical compensation of the biaxial nematic in-plane switching mode. APPLIED OPTICS 2012; 51:75-83. [PMID: 22270415 DOI: 10.1364/ao.51.000075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Accepted: 09/02/2011] [Indexed: 05/31/2023]
Abstract
Using Berreman 4 × 4 optical methods and continuum theory, we investigate the theoretical viewing properties of a potential homeotropically aligned biaxial nematic display switched with in-plane fields. We determine the isocontrast, isotransmission viewing characteristics for wide-angle viewing for in-plane switching and consider the necessary requirements for optical compensation to produce a high transmission in the bright state and low transmission in the dark state. We show how compensation can be achieved with biaxial compensation layers using a homogeneous biaxial film or from birefringence.
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Affiliation(s)
- Philip W Benzie
- Department of Engineering Science, University of Oxford, Parks Road, Oxford, OX1 3PJ, UK.
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38
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Speetjens F, Lindborg J, Tauscher T, LaFemina N, Nguyen J, Samulski ET, Vita F, Francescangeli O, Scharrer E. Low nematic onset temperatures and room temperature cybotactic behavior in 1,3,4-oxadiazole-based bent-core mesogens possessing lateral methyl groups. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm33705c] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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39
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Jeong HC, V. Le K, Gim MJ, Hur ST, Choi SW, Araoka F, Ishikawa K, Takezoe H. Transition between widened BPs by light irradiation using photo-active bent-core liquid crystal with chiral dopant. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm16650j] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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40
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Wang Y, Yoon HG, Bisoyi HK, Kumar S, Li Q. Hybrid rod-like and bent-core liquid crystal dimers exhibiting biaxial smectic A and nematic phases. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm34315k] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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41
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Jang Y, Panov VP, Kocot A, Lehmann A, Tschierske C, Vij JK. Short-range correlations seen in the nematic phase of bent-core liquid crystals by dielectric and electro-optic studies. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:060701. [PMID: 22304031 DOI: 10.1103/physreve.84.060701] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Indexed: 05/31/2023]
Abstract
Three bent-core nematic liquid crystals having the same core but with different terminal groups, short (C4) and long (C7,C9) tails, are investigated by dielectric and electro-optic contrast spectroscopic techniques. C4 shows sign reversal in the dielectric anisotropy Δε' as a function of both temperature and frequency, whereas C9 shows only negative Δε' in the entire mesophasic region. The behavior of C7 is intermediate of the two. Results of a dielectric study show that both C7 and C9 exhibit strong short-range polar correlations normal to the director. The correlation lengths of these interactions are found to be similar to those from the x-ray scattering. An increased hindered rotation for C9 compared to C4 moves the dielectric dispersion for ε(|') to much lower frequencies, such that C9 shows only negative Δε' over the entire temperature range.
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Affiliation(s)
- Yun Jang
- Department of Electronic and Electrical Engineering, Trinity College Dublin, Dublin 2, Ireland
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42
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Tallavaara P, Kantola A, Jokisaari J, Meyer T, Wilson D, Mehl G. 129Xe and 2H nuclear magnetic resonance (NMR) of xenon and deuterated-chloroform solutes in a thermotropic biaxial nematic liquid crystal. CAN J CHEM 2011. [DOI: 10.1139/v11-062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Properties of a thermotropic nematic liquid crystal (LC) TM35 (organosiloxane tetrapode) were investigated by means of nuclear magnetic resonance (NMR) spectroscopy of probe atoms and molecules. 129Xe isotope enriched xenon gas and 2H isotope enriched chloroform were used as probes. Both 129Xe and 2H NMR measurements were carried out over a wide temperature range, covering isotropic, nematic, and glass phases. A clear change in the behavior of the LC is observed within the nematic phase at 289 K by changing the temperature from low to high and inspecting the spectral line width. The derivative curve of the 129Xe chemical shift also reveals a change at 289 K. These changes may be an indication of hindered molecular rotation around the long axis, and the appearance of a biaxial nematic phase.
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Affiliation(s)
- P. Tallavaara
- NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - A.M. Kantola
- NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - J. Jokisaari
- NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FI-90014 University of Oulu, Finland
| | - T. Meyer
- Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - D.A. Wilson
- Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
| | - G.H. Mehl
- Department of Chemistry, University of Hull, Cottingham Road, Hull HU6 7RX, United Kingdom
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43
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Ostapenko T, Zhang C, Sprunt SN, Jákli A, Gleeson JT. Magneto-optical technique for detecting the biaxial nematic phase. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:021705. [PMID: 21929003 DOI: 10.1103/physreve.84.021705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 05/26/2011] [Indexed: 05/31/2023]
Abstract
The existence of the elusive biaxial phase has been the subject of much discussion since it was predicted by Freiser in 1970. More recently, there have been numerous attempts to find a thermotropic liquid crystal that exhibits a biaxial phase and with this, conflicting reports about whether such a phase has been positively identified in bent-core liquid crystals. One reason for the discrepancy is that there is currently no way to rule out surface effects or anchoring transitions, both of which may give a false positive identification of a uniaxial-biaxial nematic transition. We have developed a technique that uses a magnetic field to align the uniaxial director, thus widening its application to any bent-core nematic material.
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Affiliation(s)
- T Ostapenko
- Department of Physics, Kent State University, Kent, Ohio 44242, USA.
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44
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Kajitani T, Onouchi H, Sakurai SI, Nagai K, Okoshi K, Onitsuka K, Yashima E. Latticelike Smectic Liquid Crystal Phase in a Rigid-Rod Helical Polyisocyanide with Mesogenic Pendants. J Am Chem Soc 2011; 133:9156-9. [DOI: 10.1021/ja201133d] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takashi Kajitani
- Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Japan
| | - Hisanari Onouchi
- Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Japan
| | - Shin-ichiro Sakurai
- Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Japan
| | - Kanji Nagai
- Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Japan
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
| | - Kento Okoshi
- Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Japan
| | - Kiyotaka Onitsuka
- Department of Macromolecular Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | - Eiji Yashima
- Yashima Super-structured Helix Project, Exploratory Research for Advanced Technology (ERATO), Japan Science and Technology Agency (JST), Japan
- Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan
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45
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Lee JH, Lim TK, Yoon TH. Biaxial-uniaxial transition in a self-assembled nematic liquid crystal by field-induced molecular conformation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:051705. [PMID: 21728554 DOI: 10.1103/physreve.83.051705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2010] [Revised: 03/02/2011] [Indexed: 05/31/2023]
Abstract
A cylindrical uniaxial liquid crystal was hydrogen-bonded with a tripod-shaped molecule. As the molecular number ratio of cylindrical liquid crystal to tripod molecule converges to 2:1, |s| = 1/2 disclination defects, which are a necessary condition of biaxial nematic phase, appeared predominantly. After the application of an electric field, the |s| = 1/2 disclinations converted to |s| = 1 disclinations which imply a transition from a biaxial to uniaxial state. IR dichroism measurements support the hypothesis that the liquid crystal-tripod molecule complex undergoes a molecular conformation change from bent shape to parallel shape, and this conformation change is thought to be related to a field-induced biaxial-uniaxial transition.
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Affiliation(s)
- Ji-Hoon Lee
- School of Electrical Engineering, Pusan National University, Pusan, Korea.
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46
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Marini A, Dong RY. Density-functional-theory investigation of conformations, 13C shielding, and magnetic field interactions in a V-shaped phenylene bis carboxylate homologous series. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:041712. [PMID: 21599191 DOI: 10.1103/physreve.83.041712] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Indexed: 05/30/2023]
Abstract
Density functional theory (DFT) has been employed in a conformational study of a bent-core PBBC homologous series. IR spectra, GIAO-DFT chemical shielding tensors (CSTs), and molecular susceptibility tensors (MSTs) are theoretically calculated for various optimized conformations established by searching the potential energy surface of each PBBC V-shaped molecule. The IR results could aid the understanding of vibration normal modes, while the MST results can illuminate the alignment properties of the V-shaped molecules in an external magnetic field. CSTs of the aromatic carbons, and those previously measured by the 2D-NMR SUPER technique (with some (13)C NMR peaks reassigned for correctness based on new DFT calculations), were found to be in good agreement. These verified experimental CSTs are then used to revisit the (13)C NMR data to yield structural and local orientational order parameters for two members of the PBBC series. The PBBC series studied using the combined DFT-(13)C NMR approach strongly supports the notion that lesser populated conformational states found by DFT could be reached in the studied mesogens 10DClPBBC and 11ClPBBC upon decreasing temperature, as revealed by the change in the bend angle determined by NMR and identified with those of the DFT molecular structures optimized for various conformers.
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Affiliation(s)
- Alberto Marini
- Dipartimento di Chimica e Chimica Industriale, Universitá di Pisa, via Risorgimento 35, I-56126 Pisa, Italy
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Jokisaari JP, Kantola AM, Lounila JA, Ingman LP. Detection of phase biaxiality in liquid crystals by use of the quadrupole shift in 131Xe NMR spectra. PHYSICAL REVIEW LETTERS 2011; 106:017801. [PMID: 21231771 DOI: 10.1103/physrevlett.106.017801] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Indexed: 05/30/2023]
Abstract
An experimental method to unambiguously distinguish between uniaxial and biaxial liquid crystal phases is introduced. The method is based on the second order quadrupole shift (SOQS) observable in 131Xe NMR spectra of xenon dissolved in liquid crystals. It is shown that besides revealing the biaxiality, the 131Xe SOQS offers a novel method to determine the tilt angle in smectic C phases. As an example, the 131Xe SOQS in a ferroelectric liquid crystal is reported. It yields up a biaxial phase in between isotropic and smectic C phases.
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Affiliation(s)
- Jukka P Jokisaari
- NMR Research Group, Department of Physics, University of Oulu, Finland.
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Mathews M, Zola RS, Yang DK, Li Q. Thermally, photochemically and electrically switchable reflection colors from self-organized chiral bent-core liquid crystals. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm03479g] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Figueirinhas JL, Feio G, Cruz C, Lehmann M, Köhn C, Dong RY. Nuclear magnetic resonance spectroscopic investigations of phase biaxiality in the nematic glass of a shape-persistent V-shaped mesogen. J Chem Phys 2010; 133:174509. [DOI: 10.1063/1.3496491] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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