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The synthesis, mesomorphic and dielectric investigation of new unsymmetrical bent-core mesogens derived from 3-hydroxybenzoic acid. CHEMICAL PAPERS 2020. [DOI: 10.1007/s11696-020-01203-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Balamurugan S, Kannan P, Chuang MT, Wu SL. Antiferroelectric Bent-Core Liquid Crystals for Molecular Switching Applications. Ind Eng Chem Res 2010. [DOI: 10.1021/ie100019p] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- S. Balamurugan
- Department of Chemistry, Anna University, Chennai 600-025, India, and Department of Chemical Engineering, Tatung University, 40 Chungshan N. Rd., third sec, Taipei 104, Taiwan, ROC
| | - P. Kannan
- Department of Chemistry, Anna University, Chennai 600-025, India, and Department of Chemical Engineering, Tatung University, 40 Chungshan N. Rd., third sec, Taipei 104, Taiwan, ROC
| | - M. T. Chuang
- Department of Chemistry, Anna University, Chennai 600-025, India, and Department of Chemical Engineering, Tatung University, 40 Chungshan N. Rd., third sec, Taipei 104, Taiwan, ROC
| | - S. L. Wu
- Department of Chemistry, Anna University, Chennai 600-025, India, and Department of Chemical Engineering, Tatung University, 40 Chungshan N. Rd., third sec, Taipei 104, Taiwan, ROC
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Synthesis of Tripod-shaped Liquid Crystals with sp 3Nitrogen at the Apex. B KOREAN CHEM SOC 2009. [DOI: 10.5012/bkcs.2009.30.9.1946] [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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Kohout M, Svoboda J, Novotná V, Pociecha D, Glogarová M, Gorecka E. A nematic-polar columnar phase sequence in new bent-shaped liquid crystals based on a 7-hydroxynaphthalene-2-carboxylic acid core. ACTA ACUST UNITED AC 2009. [DOI: 10.1039/b821234a] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Izumi T, Naitou Y, Shimbo Y, Takanishi Y, Takezoe H, Watanabe J. Several Types of Bilayer Smectic Liquid Crystals with Ferroelectric and Antiferroelectric Properties in Binary Mixture of Dimeric Compounds. J Phys Chem B 2006; 110:23911-9. [PMID: 17125358 DOI: 10.1021/jp062208y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The mesomorphic behavior and phase structure were examined in the mixture of two kinds of dimeric compounds, alpha,omega-bis(4-alkoxyanilinebenzylidene-4'-carbonyloxy)pentane (mOAM5AMOm), by optical microscopy, X-ray diffraction, polarization switching, and second-harmonic generation measurements. One compound is 4OAM5AMO4 with a short terminal alkyl chain that forms a single-layer smectic phase (SmCAs) with a random mixing of spacer and tail groups. Another compound is 16OAM5AMO16 with a long terminal alkyl chain that forms a chiral, anticlinic, and antiferroelectric bilayer phase (SmCAb) with the bent molecules tilted to the bilayer. By mixing these two compounds, the SmCAs phase of 4OAM5AMO4 is easily destabilized, leading to the wide content region of the bilayer phases. In the bilayer regime, three other smectic phases are newly induced. Two of them are antiferroelectric and ferroelectric phases in which the molecules lie perpendicularly with respect to the layer. The other shows no polar response to an external electric field and behaves like a smectic A. The new appearance of these bilayer phases is discussed as a mixing effect of long and short tail groups.
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Affiliation(s)
- Tatsuya Izumi
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Ookayama, Tokyo 152-8552, Japan
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Yelamaggad CV, Shashikala IS, Hiremath US, Liao G, Jakli A, Rao DSS, Prasad SK, Li Q. Fluorine containing nonsymmetrical five-ring achiral banana-shaped compounds with columnar and synclinic antiferroelectric layered phases. SOFT MATTER 2006; 2:785-792. [PMID: 32680219 DOI: 10.1039/b608278e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The phase transitional behavior of two homologous series of five-ring banana-shaped compounds comprising fluorine substituents synthesized through covalent linking of two chemically dissimilar rod-like anisometric cores (arms) to central 1,3-phenylene is reported. The novelty of these molecules originates from the fact that the molecules are highly nonsymmetrical. One of the arms, which is either salicylaldimine or Schiff base core, possesses two vicinal fluorine atoms at the terminal ring having a -decyloxy tail; while the -alkyl tail attached to the other arm was varied to realize a homologous series of compounds. The mesophases have been characterized by several complementary studies. The banana-shaped systems having short or medium alkyl chain lengths form apolar columnar (two-dimensional) structures, while on ascending the series, a polar smectic phase is stabilized. Detailed electro-optical investigations on one of the polar smectic phases revealed a synclinic antiferroelectric (racemic) ground state structure, which switches, as expected, to an anticlinic ferroelectric state by the application of an electrical field. At higher field strengths applied for an extended time interval, the anticlinic ferroelectric state switches to a synclinic ferroelectric (chiral) state. Upon field removal, these domains switch to an anticlinic antiferroelectric (chiral) state, which eventually nucleates to the original antiferroelectric synclinic (racemic) state. Remarkably, the associated spontaneous polarization value exceeds 800 nC cm, which is among the highest reported hitherto.
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Affiliation(s)
| | | | - Uma S Hiremath
- Centre for Liquid Crystal Research, Jalahalli, Bangalore-560013, India.
| | - Guangxun Liao
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
| | - Antal Jakli
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
| | | | | | - Quan Li
- Liquid Crystal Institute, Kent State University, Kent, Ohio 44242, USA
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Nishida K, Cepic M, Kim WJ, Lee SK, Heo S, Lee JG, Takanishi Y, Ishikawa K, Kang KT, Watanabe J, Takezoe H. Interpretation of the odd-even behavior for the emergence of ferroelectricity and antiferroelectricity in bent-core mesogens. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 74:021704. [PMID: 17025449 DOI: 10.1103/physreve.74.021704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Indexed: 05/12/2023]
Abstract
Simple theoretical interpretation has been made on the previously reported odd-even behavior of the emergence of ferroelectricity and antiferroelectricity in homologous series of bent-core mesogens with the same chiral end chains (S,S) ; compounds with even and odd carbon numbers (including oxygen) exhibit ferroelectric and antiferroelectric B2 phases, respectively. The odd-even behavior was confirmed in newly synthesized racemic compounds with chiral end chains of R and S forms (R,S) together with (R,R) and (S,S) forms. According to our theoretical interpretation, ferroelectricity should be more stable in (R,S) compounds than in (S,S) compounds. Actually, the transition temperature from the isotropic phase to the Sm-CP phase was higher and the temperature range of the B2 phase was broader in the (R,S) compound than in the (S,S) compound.
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Affiliation(s)
- Koushi Nishida
- Department of Organic and Polymeric Materials, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8552, Japan
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Umadevi S, Sadashiva BK, Shreenivasa Murthy HN, Raghunathan VA. Mesogenic dimers composed of bent-core molecules with flexible alkylene spacer. SOFT MATTER 2006; 2:210-214. [PMID: 32646147 DOI: 10.1039/b516638a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The synthesis and characterization of six symmetrical mesogenic dimers composed of bent-core molecules containing alkylene spacers are reported. The mesophase was characterized by polarizing optical microscopy, differential scanning calorimetry, X-ray diffraction and electric field experiments. The X-ray diffraction studies revealed a columnar structure with an oblique lattice for the mesophase. The electric field experiments indicated a ferroelectric behaviour for the mesophase. On the basis of obtained experimental data, a possible structural model for the mesophase has been proposed.
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Affiliation(s)
- S Umadevi
- Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore-560 080, India.
| | - B K Sadashiva
- Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore-560 080, India.
| | | | - V A Raghunathan
- Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore-560 080, India.
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Reddy RA, Tschierske C. Bent-core liquid crystals: polar order, superstructural chirality and spontaneous desymmetrisation in soft matter systems. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b504400f] [Citation(s) in RCA: 777] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Takanishi Y, Takezoe H, Watanabe J, Takahashi Y, Iida A. Intralayer molecular orientation in the B1 phase of a prototype bent-core molecule P-6-O-PIMB studied by X-ray microbeam diffraction. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b514831f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Shreenivasa Murthy HN, Bodyagin M, Diele S, Baumeister U, Pelzl G, Weissflog W. Reentrant SmCPAphases: unusual polymorphism variant SmA–SmCSPA–Colob–SmCSPAobserved in new bent-core mesogens. ACTA ACUST UNITED AC 2006. [DOI: 10.1039/b516189d] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Weissflog W, Naumann G, Kosata B, Schröder MW, Eremin A, Diele S, Vakhovskaya Z, Kresse H, Friedemann R, Krishnan SAR, Pelzl G. Ten isomeric five-ring bent-core mesogens: The influence of the direction of the carboxyl connecting groups on the mesophase behaviour. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b508488a] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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