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Melnyk O, Jones R, Macêdo R, Camley RE. New quasiperiodic structures in nematic liquid crystals. SOFT MATTER 2023; 19:7644-7654. [PMID: 37779452 DOI: 10.1039/d3sm00884c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Liquid crystal molecules tend to align with each other, often forming regions of opposite alignment that meet at a boundary-topological defects. These often offer information on configuration of the liquid crystal molecules with competing constraints on their order. Here, we experimentally demonstrate a mechanism to generate topological defects in the form of spatially oscillatory domain walls in nematic liquid crystals. We initially orient the molecules perpendicular to the substrate (i.e. homeotropic alignment) and when a horizontal electric field is applied, domain walls that change their shape with time emerge. These walls form at low frequencies of the applied electric field and remain stable as the frequency increases. If the initial biasing field is at larger frequencies (kHz regime), the domain walls still form, but are not oscillatory. We develop a general theory to predict the three-dimensional liquid crystal director evolution in any two-dimensional varying field. This theory gives the time dependence for the domain walls and confirms that both the oscillatory and straight walls are stable.
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Affiliation(s)
- Olha Melnyk
- Herman B Wells Center for Pediatric Research, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- UCCS BioFrontiers Center and Department of Physics and Energy Science, University of Colorado, Colorado Springs, Colorado Springs, CO 80918, USA.
| | - Reed Jones
- UCCS BioFrontiers Center and Department of Physics and Energy Science, University of Colorado, Colorado Springs, Colorado Springs, CO 80918, USA.
| | - Rair Macêdo
- James Watt School of Engineering, Electronics & Nanoscale Engineering Division, University of Glasgow, Glasgow G12 8QQ, UK
| | - Robert E Camley
- UCCS BioFrontiers Center and Department of Physics and Energy Science, University of Colorado, Colorado Springs, Colorado Springs, CO 80918, USA.
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2
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Electric-field-induced patterns in a hockey-stick nematic. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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3
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Huh JH, Miyagawa N. Reentrant prewavy instability in competition between rising and twist modes in ac field-driven electroconvection. Phys Rev E 2021; 103:062701. [PMID: 34271653 DOI: 10.1103/physreve.103.062701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/17/2021] [Indexed: 06/13/2023]
Abstract
We report on the prewavy (PW) instability in ac field-driven electrohydrodynamics that is induced in a nematic liquid crystal (NLC) sandwiched between parallel electrodes. The instability is characterized by a twist mode of the NLC director along the vertical orientation to the electrodes (i.e., the z axis), generating a periodic pattern having a large wavelength (λ_{PW}) in the xy plane. The PW periodic to the preferred director n_{0} of the NLC should be distinguished from well-known electroconvection (EC) such as normal rolls (NRs) and abnormal rolls (ARs) with similar wave vectors. A reentrant PW (PW2) was discovered by employing well-adjusted optical conditions and a dynamic image-process method. The wavelength λ_{PW2} of the PW2 accompanying turbulent EC was measured as functions of the applied ac voltage and frequency, which was distinguished from λ_{PW1} of the primary PW (PW1) separated from the NR. Moreover, the appearance, disappearance, and reappearance of the PW were investigated for five frequency regions classified in the ac field-driven EC; it was found that the high frequency and high voltage causes competition between the rising mode (θ, tilting angle to the xy plane) and twist mode (ϕ, in-plane angle to the x axis) of the director through electrohydrodynamic coupling between the director field and flows. We discuss how the PW2 can arise by considering another twist mode known as AR instability.
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Affiliation(s)
- Jong-Hoon Huh
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
| | - Naoto Miyagawa
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
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4
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Shiomi M, Choi EJ, Huh JH. Prewavy instability-originated dielectric chevrons of electroconvection in nematic liquid crystals. Phys Rev E 2020; 102:042704. [PMID: 33212627 DOI: 10.1103/physreve.102.042704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/07/2020] [Indexed: 11/07/2022]
Abstract
This paper reports the pattern formation and evolution in a high-frequency dielectric regime observed in the AC-driven electroconvection of nematic liquid crystals (NLCs). It is determined that prewavy (PW) instability is essential for the formation and evolution. Specifically, in a twisted-aligned NLC cell, we observe a unique pattern that is comparable to the dielectric chevrons (DCVs) typically observed in a conventional planarly aligned pattern. It is determined to be a combined PW pattern with dielectric normal rolls (DNRs). Moreover, the power indices (α_{PW}, α_{DNR}, and α_{DCV}) are determined from the frequency-dependent thresholds (V_{th}∝f^{α}) of PW, DNR, and DCV. By taking into account the appearance of PW and the different power indices, the pattern evolution scenarios for DCV are proposed, which can well explain the previous experimental results. Specifically, the PW-originated DCV2 clearly differs from the defect-mediated DCV1, which is known as a typical pattern evolution.
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Affiliation(s)
- Masato Shiomi
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
| | - E-Joon Choi
- Department of Polymer Science and Engineering, Kumoh National Institute of Technology, Gumi, Gyungbuk 730-701, Korea
| | - Jong-Hoon Huh
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
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5
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Huh JH, Osoguchi H. Formation of grid patterns in an ac-driven electroconvection system. Phys Rev E 2020; 101:062701. [PMID: 32688566 DOI: 10.1103/physreve.101.062701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Accepted: 05/08/2020] [Indexed: 11/07/2022]
Abstract
We report the formation mechanism of a unique pattern observed in ac-driven electroconvection of nematic liquid crystals (NLCs), in which many well-organized grid cells are very regularly aggregated in a two-dimensional plane, globally forming a nearly perfect grid pattern (GP). Intuitively, the formation of such a pattern is unpredictable; usually, the perfectly regular normal roll (NR) showing a preferred roll direction is observed in this system by imposing a fixed initial direction of an NLC. The GP was investigated by varying the ac voltage and frequency. To characterize the GP, the density ρ_{GP}, the width a and length b of the grids, and the oscillation period T_{GP} of an inner optical pattern of the grids were measured; moreover, the lengths L[over ¯]_{x} and L[over ¯]_{y} characterizing phase-jump lines (PJLs) in the GP were examined. By taking into account the process of evolution from a fluctuating NR with defects to the GP, the velocity and director fields of the GP are estimated. Furthermore, in comparison with the bimodal mechanism proposed in the earlier study, a possible mechanism for the GP formed by the PJLs is discussed; various routes to GPs depending on the ac frequency are proposed.
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Affiliation(s)
- Jong-Hoon Huh
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
| | - Haruki Osoguchi
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
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7
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Zhang B, Kitzerow H. Pattern Formation in a Nematic Liquid Crystal Mixture with Negative Anisotropy of the Electric Conductivity-A Long-Known System with "Inverse" Light Scattering Revisited. J Phys Chem B 2016; 120:6865-71. [PMID: 27347852 DOI: 10.1021/acs.jpcb.6b05080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pattern formation in binary calamitic liquid crystal mixtures with positive dielectric anisotropy and negative conductivity anisotropy, which attracted attention owing to field-induced light scattering under unusual conditions many years ago, is reinvestigated in the conductive regime. Homeotropic cells with these mixtures exhibit a direct transition to isotropic electroconvection, while planar cells show a Fréedericksz transition to the quasi-homeotropic state and subsequent electroconvection at higher voltages. A temperature-induced change from normal and oblique convection rolls to longitudinal rolls reveals a transition from standard electroconvection to nonstandard electroconvection, which can be attributed to a sign inversion of the conductivity anisotropy. In summary, this system shows an unusually large variety of patterns and effects, which were observed and theoretically considered more recently in other systems of quite different types.
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Affiliation(s)
- Bingru Zhang
- Faculty of Science, University of Paderborn , Warburger Str. 100, 33098 Paderborn, Germany
| | - Heinz Kitzerow
- Faculty of Science, University of Paderborn , Warburger Str. 100, 33098 Paderborn, Germany
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8
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Xiang Y, Zhou MJ, Xu MY, Salamon P, Éber N, Buka Á. Unusual polarity-dependent patterns in a bent-core nematic liquid crystal under low-frequency ac field. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:042501. [PMID: 25974510 DOI: 10.1103/physreve.91.042501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Indexed: 06/04/2023]
Abstract
Electric-field-induced patterns of diverse morphology have been observed over a wide frequency range in a recently synthesized bent-core nematic (BCN) liquid crystal. At low frequencies (up to ∼25 Hz), the BCN exhibited unusual polarity-dependent patterns. When the amplitude of the ac field was enhanced, these two time-asymmetrical patterns turned into time-symmetrical prewavylike stripes. At ac frequencies in the middle-frequency range (∼50-3000 Hz), zigzag patterns were detected whose obliqueness varied with the frequency. Finally, if the frequency was increased above 3 kHz, the zigzag pattern was replaced by another, prewavylike pattern, whose threshold voltage depended on the frequency; however, the wave vector did not. For a more complete characterization, material parameters such as elastic constants, dielectric permittivities, and the anisotropy of the diamagnetic susceptibility were also determined.
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Affiliation(s)
- Ying Xiang
- School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
| | - Meng-jie Zhou
- School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
| | - Ming-Ya Xu
- School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
| | - Péter Salamon
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly Thege Miklós út 29-33, Hungary
| | - Nándor Éber
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly Thege Miklós út 29-33, Hungary
| | - Ágnes Buka
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1121 Budapest, Konkoly Thege Miklós út 29-33, Hungary
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9
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Xiang Y, Liu YK, Buka Á, Éber N, Zhang ZY, Xu MY, Wang E. Electric-field-induced patterns and their temperature dependence in a bent-core liquid crystal. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:012502. [PMID: 24580241 DOI: 10.1103/physreve.89.012502] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Indexed: 06/03/2023]
Abstract
Two kinds of electroconvection patterns in an ether-bridged bent-core nematic liquid crystal material (BCN), which appear in different frequency ranges, are examined and compared. One is a longitudinal pattern with the stripes parallel to the orientation of the BCN and with a periodicity of approximately the cell thickness, occurring in the high-frequency range of several hundreds Hz; the other one is oblique stripes, which results in a zigzag pattern, and appears in the low-frequency range of several tens Hz. In addition, within an intermediate-frequency range, transformations from oblique to longitudinal and then to normal stripes occur at increased ac voltages. In particular, we investigated the temperature behavior of longitudinal and oblique stripes: When the temperature T increases and approaches the clearing temperature Tc, the contrast of the domains is enhanced and the frequency range of existence becomes wider, while the onset voltages increase only moderately instead of diverging, thus suggesting an isotropic mechanism of pattern formation.
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Affiliation(s)
- Ying Xiang
- School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
| | - Yi-Kun Liu
- State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, Guangzhou 510275, People's Republic of China
| | - Ágnes Buka
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly Thege Miklós út 29-33, H-1121 Budapest, Hungary
| | - Nándor Éber
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly Thege Miklós út 29-33, H-1121 Budapest, Hungary
| | - Zhi-Yong Zhang
- Department of Chemistry and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, People's Republic of China
| | - Ming-Ya Xu
- School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
| | - Everett Wang
- School of Information Engineering, Guangdong University of Technology, Guangzhou 510006, People's Republic of China
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10
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Kaur S, Belaissaoui A, Goodby JW, Görtz V, Gleeson HF. Nonstandard electroconvection in a bent-core oxadiazole material. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 83:041704. [PMID: 21599183 DOI: 10.1103/physreve.83.041704] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 01/20/2011] [Indexed: 05/30/2023]
Abstract
Electroconvection (EC) phenomena have been investigated in the nematic phase of a bent-core oxadiazole material with negative dielectric anisotropy and a frequency dependent conductivity anisotropy. The formation of longitudinal roll (LR) patterns is one of the predominant features observed in the complete frequency and voltage range studied. At voltages much above the LR threshold, various complex patterns such as the "crisscrossed" pattern, bimodal varicose, and turbulence are observed. Unusually, the nonstandard EC (ns-EC) instability in this material, is observed in a regime in which we measure the dielectric and conductivity anisotropies to be negative and positive respectively. A further significant observation is that the EC displays distinct features in the high and low temperature regimes of the nematic phase, supporting an earlier report that EC patterns could distinguish between regions that have been reported as uniaxial and biaxial nematic phases.
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Affiliation(s)
- S Kaur
- School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, United Kingdom
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11
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Stamatoiu O, Mirzaei J, Feng X, Hegmann T. Nanoparticles in liquid crystals and liquid crystalline nanoparticles. Top Curr Chem (Cham) 2011; 318:331-93. [PMID: 21928012 DOI: 10.1007/128_2011_233] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Combinations of liquid crystals and materials with unique features as well as properties at the nanoscale are reviewed. Particular attention is paid to recent developments, i.e., since 2007, in areas ranging from liquid crystal-nanoparticle dispersions to nanomaterials forming liquid crystalline phases after surface modification with mesogenic or promesogenic moieties. Experimental and synthetic approaches are summarized, design strategies compared, and potential as well as existing applications discussed. Finally, a critical outlook into the future of this fascinating field of liquid crystal research is provided.
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Affiliation(s)
- Oana Stamatoiu
- Department of Chemistry, University of Manitoba, Winnipeg, MB, Canada, R3T 2N2
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12
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Urbanski M, Kinkead B, Qi H, Hegmann T, Kitzerow HS. Electroconvection in nematic liquid crystals via nanoparticle doping. NANOSCALE 2010; 2:1118-21. [PMID: 20648336 DOI: 10.1039/c0nr00139b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
It is known that a small fraction of nanoparticles dispersed in a liquid crystal can alter the electrooptic response, completely. The present study on gold nanoparticles dispersed in 5-n-heptyl-2-(4-n-octyloxy-phenyl)-pyrimidine shows that the contrast inversion observed earlier is initiated by a change from parallel to homeotropic anchoring, thereby causing an instability, which in turn leads to the appearance of convection rolls. After rapid cooling from the isotropic phase, the nanoparticle dispersion shows a regular field-induced Fréedericksz transition, like the pure liquid crystal. The electrohydrodynamic instability is presumably an example for the behavior of (+, -) systems that was predicted by de Gennes, and only recently observed experimentally for the first time.
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Affiliation(s)
- Martin Urbanski
- Department of Chemistry, Faculty of Science, University of Paderborn, Warburger Str. 100, 33098, Paderborn, Germany
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Tanaka S, Takezoe H, Eber N, Fodor-Csorba K, Vajda A, Buka A. Electroconvection in nematic mixtures of bent-core and calamitic molecules. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 80:021702. [PMID: 19792141 DOI: 10.1103/physreve.80.021702] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Indexed: 05/28/2023]
Abstract
The onset of electroconvection in binary mixtures of a bent-core and a rodlike nematic has been characterized by measuring the threshold voltage U(c) and the critical wave number of the pattern in a wide range of frequencies f. In the mixtures rich in bent-core molecules, a "conductive-prewavy2-patternless-prewavy1" morphological sequence has been detected with an unusual negative slope of U(c)(f) at high frequencies. This latter scenario seems to be related to the bent-core component, as it disappears with increasing the concentration of rodlike molecules. In addition, one of the parameters most relevant for electroconvection, the electrical conductivity, has also been varied by ionic salt doping. It has been found that the above effect of the banana-shaped molecules on the electroconvection scenarios can be suppressed by the conductivity.
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Affiliation(s)
- Shingo Tanaka
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, 2-12-1 S8-Ookayama, Meguro-Ku, Tokyo 152-8552, Japan
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14
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Wiant D, Gleeson JT, Eber N, Fodor-Csorba K, Jákli A, Tóth-Katona T. Nonstandard electroconvection in a bent-core nematic liquid crystal. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:041712. [PMID: 16383407 DOI: 10.1103/physreve.72.041712] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Indexed: 05/05/2023]
Abstract
We characterize three nonstandard electrohydrodynamic instabilities in nematic liquid crystals composed of bent-core molecules. In addition to their shape, another important attribute of this material is that the anisotropy in the electrical conductivity changes sign as the frequency of the applied electric field changes. These instabilities do not appear to fit within the standard model for electroconvection. The first instability creates a pattern with stripes parallel to the initial director orientation, with a wavelength about equal to the separation of the cell plates. The next is the previously reported prewavy instability. The third instability is optically and dynamically identical to the prewavy instability, but is distinguished by different threshold behavior.
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Affiliation(s)
- D Wiant
- Department of Physics, Kent State University, Kent, Ohio 44242, USA
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Tóth-Katona T, Gleeson JT. Conductive and dielectric defects, and anisotropic and isotropic turbulence in liquid crystals: Electric power fluctuation measurements. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 69:016302. [PMID: 14995707 DOI: 10.1103/physreve.69.016302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2003] [Indexed: 05/24/2023]
Abstract
Fluctuations of the injected electric power during electroconvection (EHC) of liquid crystals are reported in both the conductive and the dielectric regime of convection. The amplitude and the frequency of the fluctuations, as well as the probability density functions have been compared in these two regimes and substantial differences have been found both in defect turbulence of EHC and at the DSM1-->DSM2 transition.
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Affiliation(s)
- Tibor Tóth-Katona
- Department of Physics, Kent State University, P.O. Box 5190, Kent, Ohio 44242, USA
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Komineas S, Zhao H, Kramer L. Modulated structures in electroconvection in nematic liquid crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:031701. [PMID: 12689082 DOI: 10.1103/physreve.67.031701] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2002] [Indexed: 05/24/2023]
Abstract
Motivated by experiments in electroconvection in nematic liquid crystals with homeotropic alignment we study the coupled amplitude equations describing the formation of a stationary roll pattern in the presence of a weakly damped mode that breaks isotropy. The equations can be generalized to describe the planarly aligned case if the orienting effect of the boundaries is small, which can be achieved by a destabilizing magnetic field. The slow mode represents the in-plane director at the center of the cell. The simplest uniform states are normal rolls, which may undergo a pitchfork bifurcation to abnormal rolls with a misaligned in-plane director. We present a new class of defect-free solutions with spatial modulations perpendicular to the rolls. In a parameter range where the zigzag instability is not relevant these solutions are stable attractors, as observed in experiments. We also present two-dimensionally modulated states with and without defects which result from the destabilization of the one-dimensionally modulated structures. Finally, for no (or very small) damping, and away from the rotationally symmetric case, we find static chevrons made up of a periodic arrangement of defect chains (or bands of defects) separating homogeneous regions of oblique rolls with very small amplitude. These states may provide a model for a class of poorly understood stationary structures observed in various highly conducting materials ("prechevrons" or "broad domains").
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Affiliation(s)
- S Komineas
- Physikalisches Institut, Universität Bayreuth, D-95440 Bayreuth, Germany
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Huh JH, Yusuf Y, Hidaka Y, Kai S. Prewavy instability of nematic liquid crystals in a high-frequency electric field. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 66:031705. [PMID: 12366134 DOI: 10.1103/physreve.66.031705] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2002] [Indexed: 05/23/2023]
Abstract
A kind of electrohydrodynamic instability, the prewavy instability, in nematic liquid crystals is reported. The characteristic of the instability was optically investigated and discussed in comparison with some similar instabilities. Obviously the instability partially shows an isotropic feature around the nematic-isotropic transition temperature. Owing to the characteristic properties of the flow and the spatial periodicity, it should be distinguished from a previously proposed isotropic instability.
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Affiliation(s)
- Jong-Hoon Huh
- Department of Mechanical Systems Engineering, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Fukuoka 820-8502, Japan
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