1
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Zou Y, Aya S. Extended free-energy functionals for achiral and chiral ferroelectric nematic liquid crystals: theory and simulation. Phys Chem Chem Phys 2024; 26:15637-15647. [PMID: 38764421 DOI: 10.1039/d4cp00449c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2024]
Abstract
Polar nematic liquid crystals are new classes of condensed-matter states, where the inversion symmetry common to the traditional apolar nematics is broken. Establishing theoretical descriptions for the novel phase states is an urgent task. Here, we develop a Landau-type mean-field theory for both the achiral and chiral ferroelectric nematics. In the polar nematic states, the inversion symmetry breaking adds three new contributions: an additional odd elastic term (corresponding to the flexoelectricity in symmetry) to the standard Oseen-Frank free energy, electrostatic effect and an additional Landau term relating to the gradient of local polarization. The coupling between the scalar order parameter and polarization order should be considered. In the chiral and polar nematic state, we reveal that the competition between the twist elasticity and polarity dictates effective compressive energy arising from the quasi-layer structure. The polarization gradient is an essential term for describing the ferroelectric nature. Besides, we successfully simulate an experimentally reported structural transition in ferroelectric nematic droplets from a concentric-vortex-like to a line-disclination-mediated topology based on the developed theory. The approaches provide theoretical foundations for testing and predicting polar structures in emerging polar liquid crystals.
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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, China.
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, 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
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2
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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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3
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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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4
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Liu JC, Ai Y, Liu Q, Zeng YP, Chen XG, Lv HP, Xiong RG, Liao WQ. Solid-Liquid Crystal Biphasic Ferroelectrics with Tunable Biferroelectricity. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2302436. [PMID: 37202898 DOI: 10.1002/adma.202302436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/27/2023] [Indexed: 05/20/2023]
Abstract
Ferroelectricity has been separately found in numerous solid and liquid crystal materials since its first discovery in 1920. However, a single material with biferroelectricity existing in both solid and liquid crystal phases is very rare, and the regulation of biferroelectricity has never been studied. Here, solid-liquid crystal biphasic ferroelectrics, cholestanyl 4-X-benzoate (4X-CB, X = Cl, Br, and I), which exhibits biferroelectricity in both the solid and liquid crystal phases, is presented. It is noted that the ferroelectric liquid crystal phase of 4X-CB is a cholesteric one, distinct from the ordinary chiral smectic ferroelectric liquid crystal phase. Moreover, 4X-CB shows solid-solid and solid-liquid crystal phase transitions, of which the transition temperatures gradually increase from Cl to Br to I substitution. The spontaneous polarization (Ps ) of 4X-CB in both solid and liquid crystal phases can also be regulated by different halogen substitutions, where the 4Br-CB has the optimal Ps because of the larger molecular dipole moment. To the authors' knowledge, 4X-CB is the first ferroelectric with tunable biferroelectricity, which offers a feasible case for the performance optimization of solid-liquid crystal biphasic ferroelectrics.
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Affiliation(s)
- Jun-Chao Liu
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Yong Ai
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Qin Liu
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Yi-Piao Zeng
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Xiao-Gang Chen
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Hui-Peng Lv
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Ren-Gen Xiong
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
| | - Wei-Qiang Liao
- Ordered Matter Science Research Center, Nanchang University, Nanchang, 330031, P. R. China
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5
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Zhou J, Zou Y, Li J, Huang M, Aya S. Spontaneous periodic polarization wave in helielectric fluids. PNAS NEXUS 2023; 2:pgad265. [PMID: 37614674 PMCID: PMC10443924 DOI: 10.1093/pnasnexus/pgad265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 07/31/2023] [Indexed: 08/25/2023]
Abstract
By analogy with spin waves in ferromagnetic systems, the polarization (or dipole) wave is the electric counterpart that remains elusive. Here, we discover that the helielectricity, i.e. a polarization field with helicoidal helices that corresponds to a quasi-layered chiral nematic environment, causes a spontaneous formation of large-scale polarization waves in the form of the sinusoidal function. Both experimental and theoretical analyses reveal that the polarization ordering over a threshold polarization strength violates the inherent periodicity of the polarization helices, thus penalizing the compression energy. It drives a second-order structural transition to a periodically modulated polarization wave state. The roles of chirality and confinement condition are discussed.
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Affiliation(s)
- Junchen Zhou
- Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Yu Zou
- Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Jinxing Li
- Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China
| | - Mingjun Huang
- 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
| | - Satoshi Aya
- 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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6
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Sebastián N, Lovšin M, Berteloot B, Osterman N, Petelin A, Mandle RJ, Aya S, Huang M, Drevenšek-Olenik I, Neyts K, Mertelj A. Polarization patterning in ferroelectric nematic liquids via flexoelectric coupling. Nat Commun 2023; 14:3029. [PMID: 37230977 DOI: 10.1038/s41467-023-38749-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023] Open
Abstract
The recently discovered ferroelectric nematic liquids incorporate to the functional combination of fluidity, processability and anisotropic optical properties of nematic liquids, an astonishing range of physical properties derived from the phase polarity. Among them, the remarkably large values of second order optical susceptibility encourage to exploit these new materials for non-linear photonic applications. Here we show that photopatterning of the alignment layer can be used to structure polarization patterns. To do so, we take advantage of the flexoelectric effect and design splay structures that geometrically define the polarization direction. We demonstrate the creation of periodic polarization structures and the possibility of guiding polarization by embedding splay structures in uniform backgrounds. The demonstrated capabilities of polarization patterning, open a promising new route for the design of ferroelectric nematic based photonic structures and their exploitation.
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Affiliation(s)
| | - Matija Lovšin
- Jožef Stefan Institute, Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
| | - Brecht Berteloot
- Liquid Crystals and Photonics Group, ELIS Department, Ghent University, Ghent, Belgium
| | - Natan Osterman
- Jožef Stefan Institute, Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
| | - Andrej Petelin
- Jožef Stefan Institute, Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
| | - Richard J Mandle
- School of Physics and Astronomy, University of Leeds, Leeds, UK
- School of Chemistry, University of Leeds, Leeds, UK
| | - Satoshi Aya
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, 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, China
- Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou, China
| | - Irena Drevenšek-Olenik
- Jožef Stefan Institute, Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
| | - Kristiaan Neyts
- Liquid Crystals and Photonics Group, ELIS Department, Ghent University, Ghent, Belgium
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7
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Liu JC, Peng H, Chen XG, Lv HP, Song XJ, Xiong RG, Liao WQ. Fluorination Enables Dual Ferroelectricity in Both Solid- and Liquid-Crystal Phases. JACS AU 2023; 3:1196-1204. [PMID: 37124294 PMCID: PMC10131199 DOI: 10.1021/jacsau.3c00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 05/03/2023]
Abstract
Ferroelectric materials are a special type of polar substances, including solids or liquid crystals. However, obtaining a material to be ferroelectric in both its solid crystal (SC) and liquid crystal (LC) phases is a great challenge. Moreover, although cholesteric LCs inherently possess the advantage of high fluidity, their ferroelectricity remains unknown. Here, through the reasonable H/F substitution on the fourth position of the phenyl group of the parent nonferroelectric dihydrocholesteryl benzoate, we designed ferroelectric dihydrocholesteryl 4-fluorobenzoate (4-F-BDC), which shows ferroelectricity in both SC and cholesteric LC phases. The fluorination induces a lower symmetric polar P1 space group and a new solid-to-solid phase transition in 4-F-BDC. Beneficial from fluorination, the SC and cholesteric LC phases of 4-F-BDC show clear ferroelectricity, as confirmed by well-shaped polarization-voltage hysteresis loops. The dual ferroelectricity in both SC and cholesteric LC phases of a single material was rarely found. This work offers a viable case for the exploration of the interplay between ferroelectric SC and LC phases and provides an efficient approach for designing ferroelectrics with dual ferroelectricity and cholesteric ferroelectric liquid crystals.
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8
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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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9
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Kwok MH, Huang J, Rui G, Bohannon CA, Li R, Zhang H, Zhao B, Zhu L. Achieving High Permittivity Paraelectric Behavior in Mesogen-Free Sulfonylated Chiral Polyethers with Smectic C Liquid Crystalline Self-Assembly. Macromolecules 2023. [DOI: 10.1021/acs.macromol.2c02549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Man-Hin Kwok
- Department of Macromolecular Science and Engineering and Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7202, United States
| | - Jiahao Huang
- Department of Macromolecular Science and Engineering and Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7202, United States
| | - Guanchun Rui
- Department of Macromolecular Science and Engineering and Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7202, United States
| | - Caleb A. Bohannon
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Ruipeng Li
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, New York 11973, United States
| | - Honghu Zhang
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York, New York 11973, United States
| | - Bin Zhao
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Lei Zhu
- Department of Macromolecular Science and Engineering and Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106-7202, United States
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10
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Perera K, Saha R, Nepal P, Dharmarathna R, Hossain MS, Mostafa M, Adaka A, Waroquet R, Twieg RJ, Jákli A. Ferroelectric nematic droplets in their isotropic melt. SOFT MATTER 2023; 19:347-354. [PMID: 36597812 DOI: 10.1039/d2sm01395a] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The isotropic to ferroelectric nematic liquid transition was theoretically studied over one hundred years ago, but its experimental studies are rare. Here we present experimental results and theoretical considerations of novel electromechanical effects of ferroelectric nematic liquid crystal droplets coexisting with the isotropic melt. We find that the droplets have flat pancake-like shapes that are thinner than the sample thickness as long as there is room to increase the lateral droplet size. In the center of the droplets a wing-shaped defect with low birefringence is present that moves perpendicular to a weak in-plane electric field, and then extends and splits in two at higher fields. Parallel to the defect motion and extension, the entire droplet drifts along the electric field with a speed that is independent of the size of the droplet and is proportional to the amplitude of the electric field. After the field is increased above 1 mV μm-1 the entire droplet gets deformed and oscillates with the field. These observations led us to determine the polarization field and revealed the presence of a pair of positive and negative bound electric charges due to divergences of polarization around the defect volume.
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Affiliation(s)
- Kelum Perera
- Department of Physics, Kent State University, Kent OH, 44242, USA.
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
| | - Rony Saha
- Department of Physics, Kent State University, Kent OH, 44242, USA.
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
| | - Pawan Nepal
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Rohan Dharmarathna
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
| | - Md Sakhawat Hossain
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
- Materials Science Graduate Program, Kent State University, Kent OH, 44242, USA
| | - Md Mostafa
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
- Materials Science Graduate Program, Kent State University, Kent OH, 44242, USA
| | - Alex Adaka
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
- Materials Science Graduate Program, Kent State University, Kent OH, 44242, USA
| | - Ronan Waroquet
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
| | - Robert J Twieg
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH 44242, USA
| | - Antal Jákli
- Department of Physics, Kent State University, Kent OH, 44242, USA.
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent OH, 44242, USA
- Materials Science Graduate Program, Kent State University, Kent OH, 44242, USA
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11
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Yang J, Zou Y, Tang W, Li J, Huang M, Aya S. Spontaneous electric-polarization topology in confined ferroelectric nematics. Nat Commun 2022; 13:7806. [PMID: 36528675 PMCID: PMC9759571 DOI: 10.1038/s41467-022-35443-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
Topological textures have fascinated people in different areas of physics and technologies. However, the observations are limited in magnetic and solid-state ferroelectric systems. Ferroelectric nematic is the first liquid-state ferroelectric that would carry many possibilities of spatially-distributed polarization fields. Contrary to traditional magnetic or crystalline systems, anisotropic liquid crystal interactions can compete with the polarization counterparts, thereby setting a challenge in understating their interplays and the resultant topologies. Here, we discover chiral polarization meron-like structures, which appear during the emergence and growth of quasi-2D ferroelectric nematic domains. The chirality can emerge spontaneously in polar textures and can be additionally biased by introducing chiral dopants. Such micrometre-scale polarization textures are the modified electric variants of the magnetic merons. Both experimental and an extended mean-field modelling reveal that the polarization strength plays a dedicated role in determining polarization topology, providing a guide for exploring diverse polar textures in strongly-polarized liquid crystals.
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Affiliation(s)
- 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, China
| | - 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, China
| | - Wentao Tang
- 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
| | - 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.
| | - 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.
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12
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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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13
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Pociecha D, Walker R, Cruickshank E, Szydlowska J, Rybak P, Makal A, Matraszek J, Wolska JM, Storey JM, Imrie CT, Gorecka E. Intrinsically chiral ferronematic liquid crystals: An inversion of the helical twist sense at the chiral nematic – Chiral ferronematic phase transition. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119532] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Kikuchi H, Matsukizono H, Iwamatsu K, Endo S, Anan S, Okumura Y. Fluid Layered Ferroelectrics with Global C ∞v Symmetry. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202048. [PMID: 35869031 PMCID: PMC9475520 DOI: 10.1002/advs.202202048] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Ferroelectricity in fluid materials, which allows free rotation of molecules, is an unusual phenomenon raising cutting-edge questions in science. Conventional ferroelectric liquid crystals have been found in phases with low symmetry that permit the presence of spontaneous polarization. Recently, the discovery of ferroelectricity with high symmetry in the nematic phase has attracted considerable attention. However, the physical mechanism and molecular origin of ferroelectricity are poorly understood and a large domain of macroscopically oriented spontaneous polarization is difficult to fabricate in the ferroelectric nematic phase. This study reports new fluid layered ferroelectrics with the C∞v symmetry in which nearly complete orientation of the spontaneous polarization remains stable under zero electric field without any orientation treatment. These ferroelectrics are obtained by simplifying the molecular structure of a compound with a known ferroelectric nematic phase, although the simplification reduced the dipole moment. The results provide useful insights into the mechanism of ferroelectricity due to dipole-dipole interactions in molecular assemblies. The new ferroelectric materials are promising for a wide range of applications as soft ferroelectrics.
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Affiliation(s)
- Hirotsugu Kikuchi
- Kyushu UniversityInstitute for Materials Chemistry and Engineering6‐1 Kasuga‐KoenKasugaFukuoka816‐8580Japan
| | - Hiroyuki Matsukizono
- Kyushu UniversityInstitute for Materials Chemistry and Engineering6‐1 Kasuga‐KoenKasugaFukuoka816‐8580Japan
| | - Koki Iwamatsu
- Kyushu UniversityInterdisciplinary Graduate School of Engineering Sciences6‐1 Kasuga‐KoenKasugaFukuoka816‐8580Japan
| | - Sota Endo
- Kyushu UniversityInterdisciplinary Graduate School of Engineering Sciences6‐1 Kasuga‐KoenKasugaFukuoka816‐8580Japan
| | - Shizuka Anan
- Kyushu UniversityInstitute for Materials Chemistry and Engineering6‐1 Kasuga‐KoenKasugaFukuoka816‐8580Japan
| | - Yasushi Okumura
- Kyushu UniversityInstitute for Materials Chemistry and Engineering6‐1 Kasuga‐KoenKasugaFukuoka816‐8580Japan
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15
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Ide Y, Manabe Y, Inaba Y, Kinoshita Y, Pirillo J, Hijikata Y, Yoneda T, Shivakumar KI, Tanaka S, Asakawa H, Inokuma Y. Determination of the critical chain length for macromolecular crystallization using structurally flexible polyketones. Chem Sci 2022; 13:9848-9854. [PMID: 36199636 PMCID: PMC9434099 DOI: 10.1039/d2sc03083g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 07/21/2022] [Indexed: 11/21/2022] Open
Abstract
Critical chain length that divides small molecule crystallization from macromolecular crystallization is an important index in macro-organic chemistry to predict chain-length dependent properties of oligomers and polymers. However, extensive research on crystallization behavior of individual oligomers has been inhibited by difficulties in their synthesis and crystallization. Here, we report on the determination of critical chain length of macromolecular crystallization for structurally flexible polyketones consisting of 3,3-dimethylpentane-2,4-dione. Discrete polyketone oligomers were synthesized via stepwise elongation up to 20-mer. Powder and single crystal X-ray diffraction showed that the critical chain length for polyketones existed at an unexpectedly short chain length, 5-mer. While shorter oligomers adopted unique conformations and packing structures in the solid state, higher oligomers longer than 4-mer produced helical conformations and similar crystal packing. The critical chain length helped with understanding the inexplicable changes in melting point in the shorter chain length region resulting from chain conformations and packing styles.
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Affiliation(s)
- Yuki Ide
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University Kita 21, Nishi 10, Kita-ku Sapporo Hokkaido 001-0021 Japan
| | - Yumehiro Manabe
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo Hokkaido 060-8628 Japan
| | - Yuya Inaba
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo Hokkaido 060-8628 Japan
| | - Yusuke Kinoshita
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University Kita 21, Nishi 10, Kita-ku Sapporo Hokkaido 001-0021 Japan
| | - Jenny Pirillo
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University Kita 21, Nishi 10, Kita-ku Sapporo Hokkaido 001-0021 Japan
| | - Yuh Hijikata
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University Kita 21, Nishi 10, Kita-ku Sapporo Hokkaido 001-0021 Japan
| | - Tomoki Yoneda
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo Hokkaido 060-8628 Japan
| | - Kilingaru I Shivakumar
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University Kita 21, Nishi 10, Kita-ku Sapporo Hokkaido 001-0021 Japan
| | - Saki Tanaka
- Nanomaterials Research Institute (NanoMaRi), Graduate School of Natural Science and Technology, and Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Kanazawa 920-1192 Japan
| | - Hitoshi Asakawa
- Nanomaterials Research Institute (NanoMaRi), Graduate School of Natural Science and Technology, and Nano Life Science Institute (WPI-NanoLSI), Kanazawa University Kanazawa 920-1192 Japan
| | - Yasuhide Inokuma
- Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University Kita 21, Nishi 10, Kita-ku Sapporo Hokkaido 001-0021 Japan
- Division of Applied Chemistry, Faculty of Engineering, Hokkaido University Kita 13, Nishi 8, Kita-ku Sapporo Hokkaido 060-8628 Japan
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16
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Sebastián N, Čopič M, Mertelj A. Ferroelectric nematic liquid-crystalline phases. Phys Rev E 2022; 106:021001. [PMID: 36109969 DOI: 10.1103/physreve.106.021001] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Indexed: 06/15/2023]
Abstract
Recent experimental realization of ferroelectric nematic liquid crystalline phases stimulated material development and numerous experimental studies of these phases, guided by their fundamental and applicative interest. In this Perspective, we give an overview of this emerging field by linking history and theoretical predictions to a general outlook of the development and properties of the materials exhibiting ferroelectric nematic phases. We will highlight the most relevant observations to date, e.g., giant dielectric permittivity values, polarization values an order of magnitude larger than in classical ferroelectric liquid crystals, and nonlinear optical coefficients comparable with several ferroelectric solid materials. Key observations of anchoring and electro-optic behavior will also be examined. The collected contributions lead to a final discussion on open challenges in materials development, theoretical description, experimental explorations, and possible applications of the ferroelectric phases.
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Affiliation(s)
| | - Martin Čopič
- J. Stefan Institute, SI-1000 Ljubljana, Slovenia
- University of Ljubljana, Faculty of Mathematics and Physics, Ljubljana, Slovenia
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17
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Mandle RJ. A new order of liquids: polar order in nematic liquid crystals. SOFT MATTER 2022; 18:5014-5020. [PMID: 35776092 DOI: 10.1039/d2sm00543c] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Given the widespread adoption of display technology based on nematic liquid crystals, the discovery of new nematic phases at thermodynamic equilibrium, although extremely rare, generates much excitement. The remarkable discovery polar order and giant ferroelectric polarisation in a nematic fluid is a watershed moment in soft matter research, and is one of the most important discoveries in the 150 year history of liquid crystals. After a brief introduction to this emerging field, we present the current state-of-the art in terms of understanding the molecular origins of this phase, before exploring how molecular structure underpins the incidence of this phase, as well as exploring future directions.
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Affiliation(s)
- Richard J Mandle
- School of Physics and Astronomy, University of Leeds, UK, LS2 9JT
- School of Chemistry, University of Leeds, UK, LS2 9HT.
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18
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Basnet B, Rajabi M, Wang H, Kumari P, Thapa K, Paul S, Lavrentovich MO, Lavrentovich OD. Soliton walls paired by polar surface interactions in a ferroelectric nematic liquid crystal. Nat Commun 2022; 13:3932. [PMID: 35798735 PMCID: PMC9262936 DOI: 10.1038/s41467-022-31593-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 06/24/2022] [Indexed: 11/09/2022] Open
Abstract
Surface interactions are responsible for many properties of condensed matter, ranging from crystal faceting to the kinetics of phase transitions. Usually, these interactions are polar along the normal to the interface and apolar within the interface. Here we demonstrate that polar in-plane surface interactions of a ferroelectric nematic NF produce polar monodomains in micron-thin planar cells and stripes of an alternating electric polarization, separated by \documentclass[12pt]{minimal}
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\begin{document}$${180}^{{{{{{\rm{o}}}}}}}$$\end{document}180o domain walls, in thicker slabs. The surface polarity binds together pairs of these walls, yielding a total polarization rotation by \documentclass[12pt]{minimal}
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\begin{document}$${360}^{{{{{{\rm{o}}}}}}}$$\end{document}360o. The polar contribution to the total surface anchoring strength is on the order of 10%. The domain walls involve splay, bend, and twist of the polarization. The structure suggests that the splay elastic constant is larger than the bend modulus. The \documentclass[12pt]{minimal}
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\begin{document}$${360}^{{{{{{\rm{o}}}}}}}$$\end{document}360o pairs resemble domain walls in cosmology models with biased vacuums and ferromagnets in an external magnetic field. Surface interactions are usually polar along the normal to the interface and apolar within the interface. Here, the authors find that polar in-plane surface interactions produce domain structures in the bulk of a ferroelectric nematic liquid crystal.
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Affiliation(s)
- Bijaya Basnet
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA.,Materials Science Graduate Program, Kent State University, Kent, OH, 44242, USA
| | - Mojtaba Rajabi
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA.,Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Hao Wang
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA
| | - Priyanka Kumari
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA.,Materials Science Graduate Program, Kent State University, Kent, OH, 44242, USA
| | - Kamal Thapa
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA.,Department of Physics, Kent State University, Kent, OH, 44242, USA
| | - Sanjoy Paul
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA
| | - Maxim O Lavrentovich
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN, 37996, USA
| | - Oleg D Lavrentovich
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, 44242, USA. .,Materials Science Graduate Program, Kent State University, Kent, OH, 44242, USA. .,Department of Physics, Kent State University, Kent, OH, 44242, USA.
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19
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Song Y, Li J, Xia R, Xu H, Zhang X, Lei H, Peng W, Dai S, Aya S, Huang M. Development of emergent ferroelectric nematic liquid crystals with highly fluorinated and rigid mesogens. Phys Chem Chem Phys 2022; 24:11536-11543. [PMID: 35506891 DOI: 10.1039/d2cp01110g] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The emerging ferroelectric nematic liquid crystals have been attracting broader interests in new liquid crystal physics and their unique material properties. One big challenge for the ferroelectric nematic research is to enrich the material choice, which is now limited to RM734 and DIO families as representatives, in sharp contrast to the enormously diverse variety of the traditional apolar nematic liquid crystals. Here, we report a design of novel ferroelectric nematic materials with highly fluorinated and rigid mesogens. Noteworthily, they show distinct chemical structural features compared with previous aromatic ester-based molecules. The ferroelectric nematic phase was identified and confirmed through rigorous experiments. The bulk polarization was found to become purely along the long axis director, creating giant dielectric anisotropy. This work demonstrates a great potential for expanding ferroelectric nematic material diversity and will accelerate the corresponding application research and technology innovation.
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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.
| | - 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.
| | - 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.
| | - Hao Xu
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, 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, 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.
| | - Weifeng Peng
- South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter, South China University of Technology, Guangzhou 510640, China.
| | - Shuqi Dai
- 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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20
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Nada S, Hagar M, Farahat O, Hasanein AA, Emwas AH, Sharfalddin AA, Jaremko M, Zakaria MA. Three Rings Schiff Base Ester Liquid Crystals: Experimental and Computational Approaches of Mesogenic Core Orientation Effect, Heterocycle Impact. Molecules 2022; 27:2304. [PMID: 35408703 PMCID: PMC9000867 DOI: 10.3390/molecules27072304] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 12/05/2022] Open
Abstract
Three rings 2-hydroxypyridine liquid crystalline compounds have been prepared and fully characterized. The mesomorphic behavior of the prepared compounds has been investigated in terms of differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Moreover, a comparative study between the prepared compounds and previously reported analogs has been discussed in terms of the orientation and position of the mesogenic core, in addition to the direction of the terminal alkyl chains. Furthermore, a detailed computational approach has been studied to illustrate the effect of geometrical and dimensional parameters on the type of the enhanced texture and the mesomorphic range and stability. The results of the DFT study revealed that the orientation of the mesogen could affect the mesomorphic behavior and this has been attributed in terms of the degree of the polarizability of the linking groups. This result has been confirmed by calculation of the net dipole moment and the molecular electrostatic potential that show how the mesogen orientation and position could impact the molecular charge separation. Finally, the effect of the pyridyl group has been also investigated in terms of the calculated aromaticity index and the π-π stacking.
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Affiliation(s)
- Shady Nada
- Department of Chemistry, Faculty of Science, Alexandria University, Alexandria 21321, Egypt; (S.N.); (O.F.); (A.A.H.); (M.A.Z.)
| | - Mohamed Hagar
- Department of Chemistry, Faculty of Science, Alexandria University, Alexandria 21321, Egypt; (S.N.); (O.F.); (A.A.H.); (M.A.Z.)
| | - Omaima Farahat
- Department of Chemistry, Faculty of Science, Alexandria University, Alexandria 21321, Egypt; (S.N.); (O.F.); (A.A.H.); (M.A.Z.)
| | - Ahmed A. Hasanein
- Department of Chemistry, Faculty of Science, Alexandria University, Alexandria 21321, Egypt; (S.N.); (O.F.); (A.A.H.); (M.A.Z.)
| | - Abdul-Hamid Emwas
- Core Labs, King Abdullah University of Science and Technology, P.O. Box 4700, Thuwal 23955-6900, Saudi Arabia;
| | - Abeer Ali Sharfalddin
- Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia;
| | - Mariusz Jaremko
- Smart-Health Initiative (SHI) and Red Sea Research Center (RSRC), Division of Biological and Environmental Sciences and Engineering (BESE), King Abdullah University of Science and Technology (KAUST), P.O. Box 4700, Thuwal 23955-6900, Saudi Arabia;
| | - Mohamed A. Zakaria
- Department of Chemistry, Faculty of Science, Alexandria University, Alexandria 21321, Egypt; (S.N.); (O.F.); (A.A.H.); (M.A.Z.)
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21
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Rudquist P. Revealing the polar nature of a ferroelectric nematic by means of circular alignment. Sci Rep 2021; 11:24411. [PMID: 34949781 PMCID: PMC8702550 DOI: 10.1038/s41598-021-04028-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/14/2021] [Indexed: 11/09/2022] Open
Abstract
The recent discovery of spontaneously polar nematic liquid crystals-so-called ferroelectric nematics-more than a century after the first discussions about their possible existence-has attracted large interest, both from fundamental scientific and applicational points of view. However, the experimental demonstration of such a phase has, so-far, been non-trivial. Here I present a direct method for the experimental verification of a ferroelectric nematic liquid crystal phase. The method utilizes a single sample cell where the two substrates are linearly and circularly rubbed, respectively, and the ferroelectric nematic phase (NF) is revealed by the orientation of the resulting disclination lines in the cell.
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Affiliation(s)
- Per Rudquist
- Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296, Gothenburg, Sweden.
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