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Mishra VD, Pratap G, Roy A. Glassy relaxation in a de Vries smectic liquid crystal consisting of bent-core molecules. Phys Rev E 2024; 109:024703. [PMID: 38491713 DOI: 10.1103/physreve.109.024703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 02/02/2024] [Indexed: 03/18/2024]
Abstract
We report experimental investigations of a liquid crystal comprising thiophene-based achiral bent-core banana shaped molecules. The compound exhibits the following phase sequence on cooling: Isotropic (517.4 K), N (514.9 K), de Vries SmA (402 K), SmC. Practically no layer contraction was observed across the SmA to SmC transition, confirming the "de Vries" nature of the SmA phase. Interestingly, the crystallization does not occur on cooling the sample, unlike most other liquid crystals. Instead, the SmC phase undergoes a glass transition at 271 K even at a slow cooling rate. The dielectric spectroscopy studies carried out on the sample reveal the presence of a dielectric mode whose relaxation process is of the Cole-Cole type. The relaxation frequency of the mode was found to drop rapidly with decreasing temperature, confirming the glassy behavior. The variation of relaxation frequency with temperature follows the Vogel-Fulcher-Tammann equation, indicating the fragile glassy nature of the sample. This report identifies a bent-core liquid crystal exhibiting a "de Vries" SmA phase and glassy behavior at lower temperatures.
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Affiliation(s)
- Vishnu Deo Mishra
- Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080, India
| | - G Pratap
- Polymer Science and Technology, CSIR-Central Leather Research Institute, Chennai 600020, India
| | - Arun Roy
- Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560080, India
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2
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Patra D, Roy A. Spontaneous breaking of chiral symmetry in achiral bent-core liquid crystals: Excluded volume effect. Phys Rev E 2023; 107:034704. [PMID: 37072988 DOI: 10.1103/physreve.107.034704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/14/2023] [Indexed: 04/20/2023]
Abstract
Bent-Core banana-shaped molecules exhibit tilted polar smectic phases with macroscopically chiral layer order even though the constituent molecules are achiral in nature. Here, we show that the excluded volume interactions between the bent-core molecules account for this spontaneous breaking of chiral symmetry in the layer. We have numerically computed excluded volume between two rigid bent-core molecules in a layer using two types of model structures of them and explored the different possible symmetries of the layer that are favored by the excluded volume effect. For both model structures of the molecule, the C_{2} symmetric layer structure is favored for most values of tilt and bending angle. However, the C_{s} and C_{1} point symmetries of the layer are also possible for one of the model structures of the molecules. We have also developed a coupled XY-Ising model and performed Monte Carlo simulation to explain the statistical origin of spontaneous chiral symmetry breaking in this system. The coupled XY-Ising model accounts for the experimentally observed phase transitions as a function of temperature and electric field.
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Affiliation(s)
- Dipak Patra
- Soft Condensed Matter Group, Raman Research Institute, Bangalore 560080, India
| | - Arun Roy
- Soft Condensed Matter Group, Raman Research Institute, Bangalore 560080, India
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Grabovac T, Gorecka E, Zhu C, Pociecha D, Vaupotič N. Unmasking the structure of a chiral cubic thermotropic liquid crystal phase by a combination of soft and tender resonant X-ray scattering. Soft Matter 2022; 18:8194-8200. [PMID: 36269084 DOI: 10.1039/d2sm01030e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
A resonant X-ray scattering response for two structural models of a chiral cubic phase with a giant unit cell, one composed of a continuous grid and micelles and the other with three continuous grids, is studied theoretically and compared to experimental measurements. For both structural models resonant enhancement of all the symmetry-allowed diffraction peaks is predicted, as well as the existance of several symmetry forbidden peaks (pure resonant peaks). Experimental measurements were performed at the carbon and sulphur absorption edge. Only one pure resonant peak was observed, which is predicted by both models. Two low-angle symmetry allowed peaks, not observed in non-resonant scattering, were resonantly enhanced and their intensity angular dependence can distinguish between the two structural models.
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Affiliation(s)
- Timon Grabovac
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia.
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - Chenhui Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Damian Pociecha
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
| | - Nataša Vaupotič
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia.
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
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Cao Y, Tan T, Walba DM, Clark NA, Ungar G, Zhu C, Zhang L, Liu F. Understanding and Manipulating Helical Nanofilaments in Binary Systems with Achiral Dopants. Nano Lett 2022; 22:4569-4575. [PMID: 35584547 DOI: 10.1021/acs.nanolett.2c01525] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Here, we report the relationship between helical pitch of the helical nanofilament (HNF) phase formed by bent-core molecule NOBOW and the concentration of achiral dopants 5CB and octane, using linearly polarized resonant soft X-ray scattering (RSoXS). Utilizing theory-based simulation, which fits well with the experiments, the molecular helices in the filament were probed and the superstructure of helical 5CB directed by groove of HNFs was observed. Quantitative pitch determination with RSoXS reveals that helical pitch variation is related to 5CB concentration with no temperature dependence. Doping rodlike immiscible 5CB led to a pitch shortening of up to 30%, which was attributed to a change in interfacial tension. By shedding light not only on phase behavior of binary systems but also enabling control over pitch length, our work may benefit various applications of HNF-containing binary systems, including optical rotation devices, circularly polarized light emitters, and chirality transfer agents.
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Affiliation(s)
- Yu Cao
- Shaanxi International Research Center for Soft Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, P.R. China
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, P.R. China
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Tianyi Tan
- Shaanxi International Research Center for Soft Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, P.R. China
| | - David M Walba
- Department of Chemistry and Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, United States
| | - Noel A Clark
- Department of Physics and Liquid Crystal Materials Research Center, University of Colorado, Boulder, Colorado 80309, United States
| | - Goran Ungar
- Shaanxi International Research Center for Soft Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, P.R. China
| | - Chenhui Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Lei Zhang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, P.R. China
| | - Feng Liu
- Shaanxi International Research Center for Soft Matter, State Key Laboratory for Mechanical Behaviour of Materials, Xi'an Jiaotong University, Xi'an 710049, P.R. China
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Cao Y, Alaasar M, Zhang L, Zhu C, Tschierske C, Liu F. Supramolecular meso-Trick: Ambidextrous Mirror Symmetry Breaking in a Liquid Crystalline Network with Tetragonal Symmetry. J Am Chem Soc 2022; 144:6936-6945. [PMID: 35394276 DOI: 10.1021/jacs.2c01511] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Bicontinuous and multicontinuous network phases are among nature's most complex structures in soft matter systems. Here, a chiral bicontinuous tetragonal phase is reported as a new stable liquid crystalline intermediate phase at the transition between two cubic phases, the achiral double gyroid and the chiral triple network cubic phase with an I23 space group, both formed by dynamic networks of helices. The mirror symmetry of the double gyroid, representing a meso-structure of two enantiomorphic networks, is broken at the transition to this tetragonal phase by retaining uniform helicity only along one network while losing it along the other one. This leads to a conglomerate of enantiomorphic tetragonal space groups, P41212 and P43212. Phase structures and chirality were analyzed by small-angle X-ray scattering (SAXS), grazing-incidence small-angle X-ray scattering (GISAXS), resonant soft X-ray scattering (RSoXS) at the carbon K-edge, and model-dependent SAXS/RSoXS simulation. Our findings not only lead to a new bicontinuous network-type three-dimensional mesophase but also reveal a mechanism of mirror symmetry breaking in soft matter by partial meso-structure racemization at the transition from enantiophilic to enantiophobic interhelical self-assembly.
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Affiliation(s)
- Yu Cao
- Shaanxi International Research Center for Soft Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P. R. China.,MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Mohamed Alaasar
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt Mothes Str. 2, Halle (Saale) D-06120, Germany.,Department of Chemistry, Cairo University, Giza 12613, Egypt
| | - Lei Zhang
- MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, China
| | - Chenhui Zhu
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Carsten Tschierske
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt Mothes Str. 2, Halle (Saale) D-06120, Germany
| | - Feng Liu
- Shaanxi International Research Center for Soft Matter, State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an 710049, P. R. China
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6
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Kaur S, Barthakur A, Mohiuddin G, Gupta SP, Dhara S, Pal SK. Observation of “de Vries-like” properties in bent-core molecules. Chem Sci 2022; 13:2249-2257. [PMID: 35310491 PMCID: PMC8864698 DOI: 10.1039/d1sc06629c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 01/17/2022] [Indexed: 11/21/2022] Open
Abstract
“de Vries” liquid crystals, defined by a maximum layer shrinkage of ≤1% from the smectic A to C phase transition, are an integral component of ferroelectric liquid crystal (FLC) displays. Bona fide de Vries materials described in the literature are primarily perfluorinated, polysiloxane and polysilane-terminated rod-like (or calamitic) LCs. Herein, for the first time, we report a series of newly designed achiral unsymmetrical bent-core molecules with terminal alkoxy chains exhibiting similar properties to “de Vries” LCs. The new molecular structure is based on the systematic distribution of four phenyl rings attached via ester and imine linkers having 3-amino-2-methylbenzoic acid as the central core with a bent angle of 147°. Detailed microscopic investigations in differently aligned (planar as well as homeotropic) cells along with SAXS/WAXS studies revealed that the materials exhibited a SmA–SmC phase sequence along with the appearance of the nematic phase at higher temperatures. SAXS measurements divulged the layer spacings (d-spacings) and hence, the layer shrinkage was calculated ranging from 0.19% to 0.68% just below the SmA–SmC transition. The variation of the calculated molecular tilt angle (α) derived from the temperature-dependent SAXS data, followed the power law with exponent values 0.29 ± 0.01 and 0.25 ± 0.01 for compounds 1/10 and 1/12, respectively. The experimental values obtained were very close to the theoretically predicted values for the materials with de Vries-like properties. The analysis of temperature-dependent birefringence studies based on the prediction of the Landau theory, showed a dip across the SmA–SmC phase transition typical of compounds exhibiting the de Vries characteristics. The collective results obtained suggest “de Vries” SmA as a probable model for this bent-core system which may find applications in displays. A simple molecular design of unsymmetrical bent-core molecules exhibiting low layer shrinkage and a dip in the birefringence at the SmA–SmC phase transition, typical characteristics of “de Vries” liquid crystals.![]()
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Affiliation(s)
- Supreet Kaur
- Indian Institute of Science Education and Research (IISER) Mohali Sector-81, Knowledge City Manauli 140306 India
| | | | - Golam Mohiuddin
- Indian Institute of Science Education and Research (IISER) Mohali Sector-81, Knowledge City Manauli 140306 India
| | | | - Surajit Dhara
- School of Physics, University of Hyderabad Hyderabad-500046 India
| | - Santanu Kumar Pal
- Indian Institute of Science Education and Research (IISER) Mohali Sector-81, Knowledge City Manauli 140306 India
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Panarin YP, Tschierske C, Vij JK. Switching in a Biaxial Smectic A - like Phase. Liquid Crystals Today 2021. [DOI: 10.1080/1358314x.2021.1991695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Yuri P. Panarin
- Department of Electronic and Electrical Engineering, Trinity College Dublin, The University of Dublin, Dublin 2 Ireland
- Department of Electrical and Electronic Engineering, Technological University for Dublin, Dublin, Ireland
| | - Carsten Tschierske
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany
| | - Jagdish K. Vij
- Department of Electrical and Electronic Engineering, Technological University for Dublin, Dublin, Ireland
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Zhao X, Zhou J, Li J, Kougo J, Wan Z, Huang M, Aya S. Spontaneous helielectric nematic liquid crystals: Electric analog to helimagnets. Proc Natl Acad Sci U S A 2021; 118:e2111101118. [PMID: 34642251 DOI: 10.1073/pnas.2111101118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/12/2021] [Indexed: 11/18/2022] Open
Abstract
Recently, a type of ferroelectric nematic fluid has been discovered in liquid crystals in which the molecular polar nature at molecule level is amplified to macroscopic scales through a ferroelectric packing of rod-shaped molecules. Here, we report on the experimental proof of a polar chiral liquid matter state, dubbed helielectric nematic, stabilized by the local polar ordering coupled to the chiral helicity. This helielectric structure carries the polar vector rotating helically, analogous to the magnetic counterpart of helimagnet. The helielectric state can be retained down to room temperature and demonstrates gigantic dielectric and nonlinear optical responses. This matter state opens a new chapter for developing the diverse polar liquid crystal devices.
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Alaasar M, Schmidt JC, Cai X, Liu F, Tschierske C. Controlling liquid and liquid crystalline network formation by core-fluorination of hydrogen bonded supramolecular polycatenars. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.115870] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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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. Adv Mater 2020; 32:e1905591. [PMID: 32529663 DOI: 10.1002/adma.201905591] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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11
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Bader K, Müller C, Molard Y, Baro A, Ehni P, Knelles J, Laschat S. Fluorenone imidazolium salts as novel de Vries materials. RSC Adv 2020; 10:23999-24016. [PMID: 35517358 PMCID: PMC9055108 DOI: 10.1039/d0ra04650g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 06/15/2020] [Indexed: 01/09/2023] Open
Abstract
In ionic liquid crystals (ILCs) tilted mesophases such as SmC required for electro-optic devices are quite rare. We report a design concept that induced the SmC phase and enabled de Vries-like behaviour in ILCs. For this purpose, we synthesized and characterized a library of ILC derivatives ImR(On,Ym)X which consist of a rigid central fluorenone core containing an alkoxy or thioether side chain and connected via a flexible spacer to an imidazolium head group. The mesomorphic properties were studied by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and X-ray diffraction (XRD). Temperature-dependent measurements of smectic layer spacing d by small-angle X-ray scattering (SAXS) and of optical tilt angles by POM demonstrate that ILCs ImR(On,Ym)X undergo SmA–SmC phase transitions with maximum layer contraction values between 0.4% and 2.1%. The lowest reduction factor R of 0.2 at the reduced temperature T − TAC = −10 K was calculated for Im(O12,S14)Br. Electron density calculations indicated a bilayer structure. Furthermore, temperature dependent emission studies show that self-assembling has a strong influence on the emission intensity of these ILCs. ILCs consisting of cationic head group–spacer–fluorenone central core–side chain show de Vries-like behaviour.![]()
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Affiliation(s)
- Korinna Bader
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Carsten Müller
- Institut für Physikalische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Yann Molard
- CNRS, ISCR-UMR 6226, ScanMAT-UMS 2001, University Rennes 35000 Rennes France
| | - Angelika Baro
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Philipp Ehni
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Jakob Knelles
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
| | - Sabine Laschat
- Institut für Organische Chemie, Universität Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany
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Lehmann A, Alaasar M, Poppe M, Poppe S, Prehm M, Nagaraj M, Sreenilayam SP, Panarin YP, Vij JK, Tschierske C. Stereochemical Rules Govern the Soft Self-Assembly of Achiral Compounds: Understanding the Heliconical Liquid-Crystalline Phases of Bent-Core Mesogens. Chemistry 2020; 26:4714-4733. [PMID: 31859404 PMCID: PMC7186843 DOI: 10.1002/chem.201904871] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 12/15/2019] [Indexed: 11/16/2022]
Abstract
A series of bent-shaped 4-cyanoresorcinol bisterephthalates is reported. Some of these achiral compounds spontaneously form a short-pitch heliconical lamellar liquid-crystalline phase with incommensurate 3-layer pitch and the helix axis parallel to the layer normal. It is observed at the paraelectric-(anti)ferroelectric transition, if it coincides with the transition from random to uniform tilt and with the transition from anticlinic to synclinic tilt correlation of the molecules in the layers of the developing tilted smectic phase. For compounds with long chains the heliconical phase is only field-induced, but once formed it is stable in a distinct temperature range, even after switching off the field. The presence of the helix changes the phase properties and the switching mechanism from the naturally preferred rotation around the molecular long axis, which reverses the chirality, to a precession on a cone, which retains the chirality. These observations are explained by diastereomeric relations between two coexisting modes of superstructural chirality. One is the layer chirality, resulting from the combination of tilt and polar order, and the other one is the helical twist evolving between the layers. At lower temperature the helical structure is replaced by a non-tilted and ferreoelectric switching lamellar phase, providing an alternative non-chiral way for the transition from anticlinic to synclinic tilt.
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Affiliation(s)
- Anne Lehmann
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Mohamed Alaasar
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
- Department of ChemistryCairo University12613GizaEgypt
| | - Marco Poppe
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Silvio Poppe
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Marko Prehm
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
| | - Mamatha Nagaraj
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Sithara P. Sreenilayam
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Yuri P. Panarin
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Jagdish K. Vij
- Department of Electronic and Electrical EngineeringTrinity College, Dublin, The University of DublinDublin2Ireland
| | - Carsten Tschierske
- Department of ChemistryMartin Luther University Halle-WittenbergKurt Mothes Str. 206120Halle (Saale)Germany
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