1
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Pan Q, Gu ZX, Zhou RJ, Feng ZJ, Xiong YA, Sha TT, You YM, Xiong RG. The past 10 years of molecular ferroelectrics: structures, design, and properties. Chem Soc Rev 2024; 53:5781-5861. [PMID: 38690681 DOI: 10.1039/d3cs00262d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Ferroelectricity, which has diverse important applications such as memory elements, capacitors, and sensors, was first discovered in a molecular compound, Rochelle salt, in 1920 by Valasek. Owing to their superiorities of lightweight, biocompatibility, structural tunability, mechanical flexibility, etc., the past decade has witnessed the renaissance of molecular ferroelectrics as promising complementary materials to commercial inorganic ferroelectrics. Thus, on the 100th anniversary of ferroelectricity, it is an opportune time to look into the future, specifically into how to push the boundaries of material design in molecular ferroelectric systems and finally overcome the hurdles to their commercialization. Herein, we present a comprehensive and accessible review of the appealing development of molecular ferroelectrics over the past 10 years, with an emphasis on their structural diversity, chemical design, exceptional properties, and potential applications. We believe that it will inspire intense, combined research efforts to enrich the family of high-performance molecular ferroelectrics and attract widespread interest from physicists and chemists to better understand the structure-function relationships governing improved applied functional device engineering.
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Affiliation(s)
- Qiang Pan
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Zhu-Xiao Gu
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210008, P. R. China.
| | - Ru-Jie Zhou
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Zi-Jie Feng
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Yu-An Xiong
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Tai-Ting Sha
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Yu-Meng You
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
| | - Ren-Gen Xiong
- Jiangsu Key Laboratory for Science and Applications of Molecular Ferroelectrics, Southeast University, Nanjing 211189, P. R. China.
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2
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Cruickshank E. The Emergence of a Polar Nematic Phase: A Chemist's Insight into the Ferroelectric Nematic Phase. Chempluschem 2024; 89:e202300726. [PMID: 38452282 DOI: 10.1002/cplu.202300726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 02/20/2024] [Accepted: 03/07/2024] [Indexed: 03/09/2024]
Abstract
The discovery of a new polar nematic phase; the ferroelectric nematic, has generated a great deal of excitement in the field of liquid crystals. To date there have been around 150 materials reported exhibiting the ferroelectric nematic phase, in general, following three key archetypal structures with these compounds known as RM734, DIO and UUQU-4N. In this review, the relationship between the molecular structure and the stability of the ferroelectric nematic, NF, phase will be described from a chemist's perspective. This will look to highlight the wide variety of functionalities which have been incorporated into these archetypal structures and how these changes influence the transition temperatures of the mesophases present. The NF phase appears to be stabilised particularly by reducing the length of terminal alkyl chains present and adding fluorines laterally along the length of the molecular backbone. This review will look to introduce the background of the ferroelectric nematic phase before then showing the molecular structures of a range of materials which exhibit the phase, describing their structure-property relationships and therefore giving an up-to-date account of the literature for this fascinating new mesophase.
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Affiliation(s)
- Ewan Cruickshank
- School of Pharmacy and Life Sciences, Robert Gordon University, Aberdeen, AB10 7GJ, UK
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3
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Zou Y, Yang J, Zhang X, Huang M, Aya S. Topology of ferroelectric nematic droplets: the case driven by flexoelectricity or depolarization field. SOFT MATTER 2024; 20:3392-3400. [PMID: 38619075 DOI: 10.1039/d3sm01042b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
The recent discovery of ferroelectric nematics provides new opportunities for exploring polar topology in liquid matter. Here, we report numerous potential polarization topological states (e.g., polar vortex-like and line disclination mediated structures) in confined ferroelectric nematics with similar free-energy levels. In the experiment, they appear according to the confinement size and surface anchoring conditions. Based on a minimal analytical approach, we reveal that the topological transformation is balanced among the nematic elasticity, the polarization gradient, the flexoelectric and the depolarization interactions.
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Affiliation(s)
- Yu Zou
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, P. R. China.
| | - Jidan Yang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, P. R. China.
| | - Xinxin Zhang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, P. R. China.
| | - Mingjun Huang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, P. R. China.
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
| | - Satoshi Aya
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou, 510640, P. R. China.
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China
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4
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Nacke P, Manabe A, Klasen-Memmer M, Chen X, Martinez V, Freychet G, Zhernenkov M, Maclennan JE, Clark NA, Bremer M, Giesselmann F. New examples of ferroelectric nematic materials showing evidence for the antiferroelectric smectic-Z phase. Sci Rep 2024; 14:4473. [PMID: 38396051 DOI: 10.1038/s41598-024-54832-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
We present a new ferroelectric nematic material, 4-((4'-((trans)-5-ethyloxan-2-yl)-2',3,5,6'-tetrafluoro-[1,1'-biphenyl]-4-yl)difluoromethoxy)-2,6-difluorobenzonitrile (AUUQU-2-N) and its higher homologues, the molecular structures of which include fluorinated building blocks, an oxane ring, and a terminal cyano group, all contributing to a large molecular dipole moment of about 12.5 D. We observed that AUUQU-2-N has three distinct liquid crystal phases, two of which were found to be polar phases with a spontaneous electric polarization Ps of up to 6 µC cm-2. The highest temperature phase is a common enantiotropic nematic (N) exhibiting only field-induced polarization. The lowest-temperature, monotropic phase proved to be a new example of the ferroelectric nematic phase (NF), evidenced by a single-peak polarization reversal current response, a giant imaginary dielectric permittivity on the order of 103, and the absence of any smectic layer X-ray diffraction peaks. The ordinary nematic phase N and the ferroelectric nematic phase NF are separated by an antiferroelectric liquid crystal phase which has low permittivity and a polarization reversal current exhibiting a characteristic double-peak response. In the polarizing light microscope, this antiferroelectric phase shows characteristic zig-zag defects, evidence of a layered structure. These observations suggest that this is another example of the recently discovered smectic ZA (SmZA) phase, having smectic layers with the molecular director parallel to the layer planes. The diffraction peaks from the smectic layering have not been observed to date but detailed 2D X-ray studies indicate the presence of additional short-range structures including smectic C-type correlations in all three phases-N, SmZA and NF-which may shed new light on the understanding of polar and antipolar order in these phases.
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Affiliation(s)
- Pierre Nacke
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Atsutaka Manabe
- Display Solutions, Merck Electronics KGaA, 64293, Darmstadt, Germany
- Individual researcher (Since 01.01.22), 64625, Bensheim, Germany
| | | | - Xi Chen
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO, 80309, USA
| | - Vikina Martinez
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO, 80309, USA
| | - Guillaume Freychet
- Brookhaven National Laboratory, National Synchrotron Light Source-II, Upton, NY, 11973, USA
| | - Mikhail Zhernenkov
- Brookhaven National Laboratory, National Synchrotron Light Source-II, Upton, NY, 11973, USA
| | - Joseph E Maclennan
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO, 80309, USA
| | - Noel A Clark
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO, 80309, USA
| | - Matthias Bremer
- Display Solutions, Merck Electronics KGaA, 64293, Darmstadt, Germany
| | - Frank Giesselmann
- Institute of Physical Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
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5
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Brand HR, Pleiner H. Macroscopic dynamics of the ferroelectric smectic [Formula: see text] phase with [Formula: see text] symmetry. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2024; 47:10. [PMID: 38305841 DOI: 10.1140/epje/s10189-024-00406-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/05/2024] [Indexed: 02/03/2024]
Abstract
We present the macroscopic dynamics of ferroelectric smectic A, smectic [Formula: see text], liquid crystals reported recently experimentally by three groups. In this fluid and orthogonal smectic phase, the macroscopic polarization, [Formula: see text], is parallel to the layer normal thus giving rise to [Formula: see text] overall symmetry for this phase in the spatially homogeneous limit. A combination of linear irreversible thermodynamics and symmetry arguments is used to derive the resulting dynamic equations applicable at sufficiently low frequencies and sufficiently long wavelengths. Compared to non-polar smectic A phases, we find a static cross-coupling between compression of the layering and bending of the layers, which does not lead to elastic forces, but to elastic stresses. In addition, it turns out that a reversible cross-coupling between flow and the magnitude of the polarization modifies the velocities of both, first and second sound. At the same time, the relaxation of the polarization gives rise to dissipative effects for second sound at the same order of the wavevector as for the sound velocity. We also analyze reversible cross-coupling terms between elongational flow and electric fields as well as temperature and concentration gradients, which lend themselves to experimental detection. Apparently this type of terms has never been considered before for smectic phases. The question how the linear [Formula: see text] coupling in the energy alters the macroscopic response behavior when compared to usual non-polar smectic A phases is also addressed.
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Affiliation(s)
- Helmut R Brand
- Department of Physics, University of Bayreuth, 95440, Bayreuth, Germany
| | - Harald Pleiner
- Max Planck Institute for Polymer Research, 55021, Mainz, Germany.
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6
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Emelyanenko AV, Rudyak VY, Shvetsov SA, Araoka F, Nishikawa H, Ishikawa K. Transformation of polar nematic phases in the presence of an electric field. Phys Rev E 2024; 109:014701. [PMID: 38366416 DOI: 10.1103/physreve.109.014701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Accepted: 12/07/2023] [Indexed: 02/18/2024]
Abstract
Only a few years have passed since the discovery of polar nematics, and now they are becoming the most actively studied liquid-crystal materials. Despite numerous breakthrough findings made recently, a theoretical systematization is still lacking. In the present paper, we take a step toward systematization. The powerful technique of molecular-statistical physics has been applied to an assembly of polar molecules influenced by electric field. Three polar nematic phases were found to be stable at various conditions: the double-splay ferroelectric nematic N_{F}^{2D} (observed in the lower-temperature range in the absence of or at low electric field), the double-splay antiferroelectric nematic N_{AF} (observed at intermediate temperature in the absence of or at low electric field), and the single-splay ferroelectric nematic N_{F}^{1D} (observed at moderate electric field at any temperature below transition into paraelectric nematic N and in the higher-temperature range (also below N) at low electric field or without it. A paradoxical transition from N_{F}^{1D} to N induced by application of higher electric field has been found and explained. A transformation of the structure of polar nematic phases at the application of electric field has also been investigated by Monte Carlo simulations and experimentally by observation of polarizing optical microscope images. In particular, it has been realized that, at planar anchoring, N_{AF} in the presence of a moderate out-of-plane electric field exhibits twofold splay modulation: antiferroelectric in the plane of the substrate and ferroelectric in the plane normal to the substrate. Several additional subtransitions related to fitting the confined geometry of the cell by the structure of polar phases were detected.
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Affiliation(s)
| | - V Yu Rudyak
- Lomonosov Moscow State University, Moscow 119991, Russia
| | - S A Shvetsov
- Lomonosov Moscow State University, Moscow 119991, Russia
| | - F Araoka
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa Wako, Saitama 351-0198, Japan
| | - H Nishikawa
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa Wako, Saitama 351-0198, Japan
| | - K Ishikawa
- Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan
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7
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Hsiao YT, Nys I, Neyts K. Lateral electric field switching in thin ferroelectric nematic liquid crystal cells. SOFT MATTER 2023; 19:8617-8624. [PMID: 37916445 DOI: 10.1039/d3sm00997a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
This study shows that, in cells with small thicknesses, the permanent polarization in the ferroelectric nematic phase of RM734 is aligned in the direction opposite to the rubbing direction. The electrode configuration induces an in-plane field near one substrate and a normal field near the other substrate. At low voltages, the permanent polarization rotates parallel to the substrate plane when its original orientation is at an angle with the electric field. The rotation occurs over a distance of more than 100 μm, where the applied electric field is very small. At higher voltages, the polarization aligns perpendicularly to the substrates under the influence of the transverse electric field. After removing the voltage, sometimes a slow reorientation of the polarization can be observed, which is ascribed to the slow release of ionic species. The results provide insight into the complex mechanisms that are involved in the switching of ferroelectric nematic liquid crystals.
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Affiliation(s)
- Yu-Tung Hsiao
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark 126, Ghent, Belgium.
| | - Inge Nys
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark 126, Ghent, Belgium.
| | - Kristiaan Neyts
- LCP Group, Department of Electronics and Information Systems, Ghent University, Technologiepark 126, Ghent, Belgium.
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8
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Karcz J, Rychłowicz N, Czarnecka M, Kocot A, Herman J, Kula P. Enantiotropic ferroelectric nematic phase in a single compound. Chem Commun (Camb) 2023. [PMID: 37937977 DOI: 10.1039/d3cc04296k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
The ferroelectric nematic phase became the centre of interest of scientists because of its unique physical properties. The uniqueness of this particular phase results in its monotropic character in all known NF materials. Here we present the very first example of a compound with an enantiotropic ferroelectric nematic phase. Compound 3JK is complementary with already well known NF materials, i.e. RM734 and DIO and is characterized by moderately high dielectric anisotropy.
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Affiliation(s)
- Jakub Karcz
- Institute of Chemistry, Faculty of Advanced Technologies and Chemistry, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Natan Rychłowicz
- Institute of Chemistry, Faculty of Advanced Technologies and Chemistry, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Małgorzata Czarnecka
- Faculty of Electrical Engineering, Automatics, Computer Science and Biomedical Engineering, AGH University of Science and Technology, al. Adama Mickiewicza 30, 30-059 Cracow, Poland
| | - Antoni Kocot
- Institute of Materials Engineering, Faculty of Science and Technology, University of Silesia, ul. 75 Pułku Piechoty, 41-500 Chorzów, Poland
| | - Jakub Herman
- Institute of Chemistry, Faculty of Advanced Technologies and Chemistry, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland.
| | - Przemysław Kula
- Institute of Chemistry, Faculty of Advanced Technologies and Chemistry, Military University of Technology, ul. gen. S. Kaliskiego 2, 00-908 Warsaw, Poland.
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9
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Kubala P, Cieśla M, Longa L. Splay-induced order in systems of hard tapers. Phys Rev E 2023; 108:054701. [PMID: 38115523 DOI: 10.1103/physreve.108.054701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 10/12/2023] [Indexed: 12/21/2023]
Abstract
The main objective of this work is to clarify the role that taper-shaped elongated molecules, i.e., molecules with one end wider than the other, can play in stabilizing orientational order. The focus is exclusively on entropy-driven self-organization induced by purely excluded volume interactions. Drawing an analogy to RM734 (4-[(4-nitrophenoxy)carbonyl]phenyl-2,4-dimethoxybenzoate), which is known to stabilize ferroelectric nematic (N_{F}) and nematic splay (N_{S}) phases, and assuming that molecular biaxiality is of secondary importance, we consider monodisperse systems composed of hard molecules. Each molecule is modeled using six collinear tangent spheres with linearly decreasing diameters. Through hard-particle, constant-pressure Monte Carlo simulations, we study the emergent phases as functions of the ratio between the smallest and largest diameters of the spheres (denoted as d) and the packing fraction (η). To analyze global and local molecular orderings, we examine molecular configurations in terms of nematic, smectic, and hexatic order parameters. Additionally, we investigate the radial pair distribution function, polarization correlation function, and the histogram of angles between molecular axes. The last characteristic is utilized to quantify local splay. The findings reveal that splay-induced deformations drive unusual long-range orientational order at relatively high packing fractions (η>0.5), corresponding to crystalline phases. When η<0.5, only short-range order is affected, and in addition to the isotropic liquid, only the standard nematic and smectic-A liquid crystalline phases are stabilized. However, for η>0.5, apart from the ordinary nonpolar hexagonal crystal, three additional frustrated crystalline polar blue phases with long-range splay modulation are observed: antiferroelectric splay crystal (Cr_{S}P_{A}), antiferroelectric double-splay crystal (Cr_{DS}P_{A}), and ferroelectric double-splay crystal (Cr_{DS}P_{F}). Finally, we employ Onsager-Parsons-Lee local density functional theory to investigate whether any sterically induced (anti)ferroelectric nematic or smectic-A type of ordering is possible for our system, at least in a metastable regime.
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Affiliation(s)
- Piotr Kubala
- Institute of Theoretical Physics, Jagiellonian University in Kraków, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Michał Cieśla
- Institute of Theoretical Physics, Jagiellonian University in Kraków, Łojasiewicza 11, 30-348 Kraków, Poland
| | - Lech Longa
- Institute of Theoretical Physics, Jagiellonian University in Kraków, Łojasiewicza 11, 30-348 Kraków, Poland
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10
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Cruickshank E, Rybak P, Majewska MM, Ramsay S, Wang C, Zhu C, Walker R, Storey JMD, Imrie CT, Gorecka E, Pociecha D. To Be or Not To Be Polar: The Ferroelectric and Antiferroelectric Nematic Phases. ACS OMEGA 2023; 8:36562-36568. [PMID: 37810647 PMCID: PMC10552116 DOI: 10.1021/acsomega.3c05884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/30/2023] [Indexed: 10/10/2023]
Abstract
We report two new series of compounds that show the ferroelectric nematic, NF, phase in which the terminal chain length is varied. The longer the terminal chain, the weaker the dipole-dipole interactions of the molecules are along the director and thus the lower the temperature at which the axially polar NF phase is formed. For homologues of intermediate chain lengths, between the non-polar and ferroelectric nematic phases, a wide temperature range nematic phase emerges with antiferroelectric character. The size of the antiparallel ferroelectric domains critically increases upon transition to the NF phase. In dielectric studies, both collective ("ferroelectric") and non-collective fluctuations are present, and the "ferroelectric" mode softens weakly at the N-NX phase transition because the polar order in this phase is weak. The transition to the NF phase is characterized by a much stronger lowering of the mode relaxation frequency and an increase in its strength, and a typical critical behavior is observed.
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Affiliation(s)
- Ewan Cruickshank
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Paulina Rybak
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Magdalena M. Majewska
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Shona Ramsay
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Cheng Wang
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Chenhui Zhu
- Advanced
Light Source, Lawrence Berkeley National
Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Rebecca Walker
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - John M. D. Storey
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Corrie T. Imrie
- Department
of Chemistry, School of Natural and Computing Sciences, University of Aberdeen, Aberdeen AB24 3UE, U.K.
| | - Ewa Gorecka
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Damian Pociecha
- Faculty
of Chemistry, University of Warsaw, ul. Zwirki i Wigury 101, 02-089 Warsaw, Poland
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11
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Szydlowska J, Majewski P, Čepič M, Vaupotič N, Rybak P, Imrie CT, Walker R, Cruickshank E, Storey JMD, Damian P, Gorecka E. Ferroelectric Nematic-Isotropic Liquid Critical End Point. PHYSICAL REVIEW LETTERS 2023; 130:216802. [PMID: 37295101 DOI: 10.1103/physrevlett.130.216802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/18/2023] [Indexed: 06/12/2023]
Abstract
A critical end point above which an isotropic phase continuously evolves into a polar (ferroelectric) nematic phase with an increasing electric field is found in a ferroelectric nematic liquid crystalline material. The critical end point is approximately 30 K above the zero-field transition temperature from the isotropic to nematic phase and at an electric field of the order of 10 V/μm. Such systems are interesting from the application point of view because a strong birefringence can be induced in a broad temperature range in an optically isotropic phase.
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Affiliation(s)
- Jadwiga Szydlowska
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Pawel Majewski
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Mojca Čepič
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Department of Physics and Technical Studies, Faculty of Education, University of Ljubljana, Kardeljeva ploščad 16, 1000 Ljubljana, Slovenia
| | - Nataša Vaupotič
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, 2000 Maribor, Slovenia
| | - Paulina Rybak
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Corrie T Imrie
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - Rebecca Walker
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - Ewan Cruickshank
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - John M D Storey
- Department of Chemistry, University of Aberdeen, Old Aberdeen AB24 3UE, United Kingdom
| | - Pociecha Damian
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Ewa Gorecka
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
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12
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Tufaha N, Cruickshank E, Pociecha D, Gorecka E, Storey JM, Imrie CT. Molecular Shape, Electronic Factors, and the Ferroelectric Nematic Phase: Investigating the Impact of Structural Modifications. Chemistry 2023; 29:e202300073. [PMID: 36807424 PMCID: PMC10962687 DOI: 10.1002/chem.202300073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023]
Abstract
The synthesis and characterisation of two series of low molar mass mesogens, the (4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3.m) and the (3-fluoro-4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3F.m), are reported in order to investigate the effect of changing the position of a lateral alkoxy chain from the methoxy-substituted terminal ring to the central phenyl ring in these two series of materials based on RM734. All members of the NT3.m series exhibited a conventional nematic phase, N, which preceded the ferroelectric nematic phase, NF , whereas all the members of the NT3F.m series exhibited direct NF -I transitions except for NT3F.1 which also exhibited an N phase. These materials cannot be described as wedge-shaped, yet their values of the ferroelectric nematic-nematic transition temperature, TN F N ${{_{{\rm N}{_{{\rm F}}}{\rm N}}}}$ , exceed those of the corresponding materials with the lateral alkoxy chain located on the methoxy-substituted terminal ring. In part, this may be attributed to the effect that changing the position of the lateral alkoxy chain has on the electronic properties of these materials, specifically on the electron density associated with the methoxy-substituted terminal aromatic ring. The value of TNI decreased with the addition of a fluorine atom ortho to the nitro group in NT3F.1, however, the opposite behaviour was found when the transition temperatures of the NF phase were compared which are higher for the NT3F.m series. This may reflect a change in the polarity and polarizability of the NT3F.m series compared to the NT3.m series. Therefore, it is suggested that, rather than simply promoting a tapered shape, the role of the lateral chain in inhibiting anti-parallel associations and its effect on the electronic properties of the molecules are the key factors in driving the formation of the NF phase.
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Affiliation(s)
- Naila Tufaha
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
| | - Ewan Cruickshank
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
| | - Damian Pociecha
- Faculty of ChemistryUniversity of Warsawul. Zwirki i Wigury 10102-089WarsawPoland
| | - Ewa Gorecka
- Faculty of ChemistryUniversity of Warsawul. Zwirki i Wigury 10102-089WarsawPoland
| | - John M.D. Storey
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
| | - Corrie T. Imrie
- Department of ChemistryUniversity of AberdeenOld AberdeenAB24 3UEUK
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Yu JS, Lee JH, Lee JY, Kim JH. Alignment properties of a ferroelectric nematic liquid crystal on the rubbed substrates. SOFT MATTER 2023; 19:2446-2453. [PMID: 36939059 DOI: 10.1039/d3sm00123g] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The orientation characteristics of FNLC-919, a new material with a ferroelectric nematic phase at room temperature, were investigated. Its alignment characteristics varied greatly depending on the relative rubbing direction on both substrates of a liquid crystal cell. In a cell where the two substrates were rubbed in the same direction, they were arranged homogeneously along the rubbing direction without domains or defects in the ferroelectric nematic phase. In a cell where the two substrates were rubbed in the anti-parallel direction, the two domains were twisted in the opposite direction. We quantitatively obtained the twisted direction and angle by matching the experimental data and calculation results using Jones matrix calculations. From the electro-optical experiment, it was confirmed that the polarization direction was opposite to the rubbing direction. In addition, the wavelength and temperature dependence of birefringence was measured for FNLC-919. In a cell where the rubbing direction between two substrates was 90°, two domains of opposite directions were observed in the nematic phase. When it becomes a ferroelectric nematic phase on cooling, the twist is determined to be only in one direction. The twist direction and angle were quantitatively obtained in the nematic and ferroelectric nematic phases. It was twisted more in the ferroelectric nematic phase than in the nematic phase.
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Affiliation(s)
- Jeong-Seon Yu
- Institute of Quantum Systems, Chungnam National University, Daejeon, 34134, Korea.
| | - Jae Hoon Lee
- Department of Physics, Chungnam National University, Daejeon, 34134, Korea
| | - Jun-Yong Lee
- Department of Physics, Chungnam National University, Daejeon, 34134, Korea
| | - Jong-Hyun Kim
- Institute of Quantum Systems, Chungnam National University, Daejeon, 34134, Korea.
- Department of Physics, Chungnam National University, Daejeon, 34134, Korea
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14
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Song Y, Deng M, Wang Z, Li J, Lei H, Wan Z, Xia R, Aya S, Huang M. Emerging Ferroelectric Uniaxial Lamellar (Smectic A F) Fluids for Bistable In-Plane Polarization Memory. J Phys Chem Lett 2022; 13:9983-9990. [PMID: 36263973 DOI: 10.1021/acs.jpclett.2c02846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The emerging matter category of liquid-matter ferroelectrics, i.e., ferroelectric nematics, demonstrates an unprecedented combination of fluidity and spontaneous polarization. However, unlike traditional ferroelectrics, the field-switched polarization at zero-field cannot be conserved, so the memory effect remains challenging. Here we report another new type of ferroelectric liquid crystal state, dubbed the ferroelectric smectic A phase, where the polarization is longitudinally coupled to the smectic quasi-layer order. With higher packing density, the phase exhibits higher values of refractive anisotropy and spontaneous polarization compared to the ferroelectric nematics. A delicate balance between the liquid crystal elasticity and flow viscosity enables both the switching and memory of the polarization field, thus opening the door toward realizing liquid-matter ferroelectric memory devices.
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Affiliation(s)
- Yaohao Song
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Minghui Deng
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Zhidong Wang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Jinxing Li
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Huanyu Lei
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Zhe Wan
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Runli Xia
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Satoshi Aya
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou 510640, China
| | - Mingjun Huang
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou 510640, China
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