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Yamamura Y, Ito M, Sugai K, Noda H, Galewski Z, Saito K. Molecular aggregation in liquid-crystalline layers crucially affects their physics: smectic A (SmA)-nematic (N) phase transition. SOFT MATTER 2023; 19:7245-7254. [PMID: 37724464 DOI: 10.1039/d3sm00958k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/20/2023]
Abstract
Recently, two molecular packing modes of the alkyl chain in smectic A (SmA) liquid crystal phases were revealed: normal and tilted types, which are named by the orientation relative to the layer normal. This study reveals the relationship between the packing mode and thermodynamic order of the SmA-nematic (N) phase transition. Two normal type and three tilted type mesogens were subject to thermodynamic and structural experiments. The DSC results showed that the SmA-N phase transitions of the normal and tilted types are of the second and first order, respectively. The analysis of the intensities of reflections in wide-angle X-ray diffraction related to the periodicity of the SmA layer yielded the distribution of the mass centers of molecules along the normal to the SmA layers. The resultant distribution offered a rationale for the correlation of the thermodynamic order of the SmA-N phase transition and molecular packing modes in the SmA phases based on the Meyer-Lubensky theory.
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Affiliation(s)
- Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Mizuki Ito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Kazutaka Sugai
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Hiroshi Noda
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Zbigniew Galewski
- The Faculty of Chemistry, University of Wrocław, Wrocław 50-383, Poland
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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Deptuch A, Jaworska-Gołąb T, Dziurka M, Hooper J, Srebro-Hooper M, Urbańska M, Tykarska M, Marzec M. Determination of tilt angle and its behavior in chiral smectic phases by exploring molecular conformations using complementary methods. Phys Rev E 2023; 107:034703. [PMID: 37072974 DOI: 10.1103/physreve.107.034703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 02/21/2023] [Indexed: 04/20/2023]
Abstract
Density functional theory (DFT) calculations and x-ray diffraction techniques were employed to evaluate the value of the tilt angle in ferroelectric smectic C^{*} and antiferroelectric smectic C_{A}^{*} phases. Five homologues from the chiral series denoted as 3FmHPhF6(m=2,4,5,6,7), based on 4-(1-methylheptyloxycarbonyl) phenyl 4'-octyloxybiphenyl-4-carboxylate (MHPOBC), were studied. Two types of conformations for the nonchiral terminal chain (fully extended and gauche) and three types of deviation from the rodlike shape of the molecules (hockey stick, zigzag, and C shape) were computationally considered. The nonlinear shape of the molecules was accounted for by introducing a shape parameter δΘ. We observe that calculations of the tilt angle which consider the C-shaped structures, in both the fully extended or gauche conformations, lead to good agreement with the values of the tilt angle obtained from electro-optical measurements below the saturation temperature. The results allow us to conclude that such structures are adopted by molecules in the examined series of smectogens. Additionally, this study proves the presence of the standard orthogonal SmA^{*} phase for the homologues with m=6, 7, and the de Vries SmA^{*} phase for m=5.
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Affiliation(s)
- A Deptuch
- Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego 152, PL-31342 Kraków, Poland
| | - T Jaworska-Gołąb
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
| | - M Dziurka
- Faculty of Chemisty, Jagiellonian University, Gronostajowa 2, PL-30387 Kraków, Poland
| | - J Hooper
- Faculty of Chemisty, Jagiellonian University, Gronostajowa 2, PL-30387 Kraków, Poland
| | - M Srebro-Hooper
- Faculty of Chemisty, Jagiellonian University, Gronostajowa 2, PL-30387 Kraków, Poland
| | - M Urbańska
- Institute of Chemistry, Military University of Technology, Kaliskiego 2, PL-00908 Warsaw, Poland
| | - M Tykarska
- Institute of Chemistry, Military University of Technology, Kaliskiego 2, PL-00908 Warsaw, Poland
| | - M Marzec
- M. Smoluchowski Institute of Physics, Jagiellonian University, Łojasiewicza 11, PL-30348 Kraków, Poland
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Vasanthi T, Chitravel T, Balasubramanian V, Balamuralikrishnan S, Vijayakumar VN. Impact of core polarity on smectic B-induced hydrogen bond liquid crystals. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2023; 46:5. [PMID: 36780059 DOI: 10.1140/epje/s10189-023-00263-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Accepted: 01/25/2023] [Indexed: 06/18/2023]
Abstract
The novel series of hydrogen bond liquid crystals were synthesized from the 2-methylglutaric acid (MGA) and 4-alkyloxybenzoic acid (nOBA) compounds. The induced smectic B phase with different texture (spine texture, needle texture, mosaic texture, natural mosaic texture and marble texture) were identified by polarizing optical microscope. Due to breaking of in-plane rotational symmetry within molecular layers, smectic B phase is tempted by suppressing other usual mesophases. The mesomorphic transition temperature, enthalpy and entropy values were calculated by differential scanning calorimeter which strongly proves the existence of mesomorphism. H-bond interaction and functional groups were confirmed by the observed peak between 2910 and 2954 cm-1 in the FTIR spectra. Thermal stability and extended mesophase width (for MGA + 12OBA = 31.1) of Sm B mesophase were reported and it clearly reveals the existence of mono-phase variance in the MGA + nOBA HBLC complex. Due to the steric effect, and the increased molecular core polarity, the highly stabilized Sm B phase with different textures were observed while varying alkyloxy carbon number n = 7 to 12. Further, the origination of Sm B phase and its detailed characteristics were reported.
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Affiliation(s)
- T Vasanthi
- Department of Physics, Condensed Matter Research Laboratory (CMRL), Research Park, Bannari Amman Institute of Technology, Sathyamangalam, Tamilnadu, 638 401, India
| | - T Chitravel
- Department of Physics, Anna University Engineering College, Ramanathapuram, 623 513, India
| | - V Balasubramanian
- Department of Physics, Sona College of Technology, Salem, Tamil Nadu, 636 005, India
| | - S Balamuralikrishnan
- Department of Physics (DDE), Annamalai University, Annamalainagar, 608002, India
| | - V N Vijayakumar
- Department of Physics, Condensed Matter Research Laboratory (CMRL), Research Park, Bannari Amman Institute of Technology, Sathyamangalam, Tamilnadu, 638 401, India.
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Oka T, Yamamura Y, Kutsumizu S, Saito K. Aggregation structure of chiral cubic liquid crystals revealed by X-ray diffraction utilizing a new algorithm. SOFT MATTER 2023; 19:1194-1201. [PMID: 36655785 DOI: 10.1039/d2sm01687g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Chiral aggregation structure spontaneously formed by achiral rodlike molecules, a long-time unsolved problem in liquid crystal science, has been clarified by applying a new crystallographic algorithm recently developed while utilizing aggregation characteristics of this type. Bicontinuously interwoven networks characterize it similarly to the neighboring Gyroid phase in a phase diagram against the alkyl chain length and temperature. However, the network connectivity is significantly different from the bicontinuous networks that have been either known for related compounds or assumed for this phase. The network is compatible with the homochiral arrangement of rodlike molecules with successive twists by a proper angle between adjacent junctions.
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Affiliation(s)
- Toshihiko Oka
- Department of Physics, Faculty of Science, and Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka 422-8529, Japan
| | - Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Shoichi Kutsumizu
- Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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Dryzek E, Juszyńska-Gałązka E, Zaleski R, Jasińska B, Eusébio MES. Free volume in the smectic-E phase of 4-hexyl-4' isothiocyanatobiphenyl studied by positron annihilation spectroscopy. Phys Rev E 2020; 101:022705. [PMID: 32168647 DOI: 10.1103/physreve.101.022705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/08/2020] [Indexed: 06/10/2023]
Abstract
Positron annihilation lifetime spectroscopy has been used to study 4-hexyl-4'-isothiocyanatobiphenyl. Changes of the orthopositronium lifetime parameters with temperature have been observed for the supercooled smectic-E phase. The measurements confirm that positronium is created and annihilates in a layer of a lower electron density containing alkyl chains of molecules. The two-state bond-lattice model of glass transition explains the thermal activation of the centers where orthopositronium is created and annihilates when the glass of the smectic-E phase softens. However, the subsequent cold crystallization of the softened regions also influences the orthopositronium lifetime and intensity, which complicates the picture seen by positrons. The measurements during isothermal crystallization suggest that it progresses in two stages. The first stage can be described by the Avrami equation with the Avrami exponent close to unity, which indicates low-dimensional crystallization. Similarly to liquid n alkanes, the application of pressure is equivalent to temperature lowering with the similar equivalence relationship between pressure and temperature, which seems to confirm the structure of the smectic-E phase with sublayers containing alkyl chains in a molten state. The dependence of the orthopositronium lifetime on pressure for the smectic-E phase may be described by the bubble model where the positronium bubble is approximated with a finite square potential well with the depth of U=1.45eV.
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Affiliation(s)
- E Dryzek
- Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
| | - E Juszyńska-Gałązka
- Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Kraków, Poland
| | - R Zaleski
- Institute of Physics, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - B Jasińska
- Institute of Physics, Maria Curie-Skłodowska University, Pl. M. Curie-Skłodowskiej 1, 20-031 Lublin, Poland
| | - M E S Eusébio
- CQC Departamento de Quimica, Universidade de Coimbra, Rua Larga 3004-534 Coimbra, Portugal
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Yamamura Y, Nakazawa Y, Kutsumizu S, Saito K. Molecular packing in two bicontinuous Ia3[combining macron]d gyroid phases of calamitic cubic mesogens BABH(n): roles in structural stability and reentrant behavior. Phys Chem Chem Phys 2019; 21:23705-23712. [PMID: 31633143 DOI: 10.1039/c9cp04424h] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
1,2-Bis(4'-n-alkoxybenzoyl)hydrazine [BABH(n), n is the number of carbon atoms in the alkyl chain] exhibits two different Ia3[combining macron]d cubic phases depending on the chain length (5 ≤n≤ 13 and 15 ≤n≤ 22). The molecular packing modes, not only of molecular cores but also of alkyl chains, are investigated through a maximum entropy method (MEM) and an analysis of the chain-length dependence of the body diagonal of the unit cell. The analyses revealed the difference in molecular packing. The short-chain Ia3[combining macron]d structure of BABH(n) (5 ≤n≤ 13) is constructed by single-layered core motifs and bilayers of alkyl chains, in which the orientation is tilted from the normal to the layer. The long-chain Ia3[combining macron]d structure (15 ≤n≤ 22) is formed by double-layered core motifs and monolayers of alkyl chains, in which the orientation is normal to the layer. Based on the molecular packing modes, the reentrant behavior between the two Ia3[combining macron]d phases was clarified. It was revealed that the alkyl chains of BABH(n) molecules play an essential role in the formation and stability of the two Ia3[combining macron]d structures.
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Affiliation(s)
- Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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de Oliveira AH, Silva WP, da Silva JK, Freitas J, de Souza MA, Cristiano R, Menezes FG. Non-symmetrical three and two-core ring mesogens based on quinoxaline and benzimidazole derivatives: Supramolecular layers through amphoteric donating/accepting H-bonds. J Mol Struct 2019. [DOI: 10.1016/j.molstruc.2018.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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