1
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Wang CI, Maier JC, Jackson NE. Accessing the electronic structure of liquid crystalline semiconductors with bottom-up electronic coarse-graining. Chem Sci 2024; 15:8390-8403. [PMID: 38846409 PMCID: PMC11151863 DOI: 10.1039/d3sc06749a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 05/01/2024] [Indexed: 06/09/2024] Open
Abstract
Understanding the relationship between multiscale morphology and electronic structure is a grand challenge for semiconducting soft materials. Computational studies aimed at characterizing these relationships require the complex integration of quantum-chemical (QC) calculations, all-atom and coarse-grained (CG) molecular dynamics simulations, and back-mapping approaches. However, these methods pose substantial computational challenges that limit their application to the requisite length scales of soft material morphologies. Here, we demonstrate the bottom-up electronic coarse-graining (ECG) of morphology-dependent electronic structure in the liquid-crystal-forming semiconductor, 2-(4-methoxyphenyl)-7-octyl-benzothienobenzothiophene (BTBT). ECG is applied to construct density functional theory (DFT)-accurate valence band Hamiltonians of the isotropic and smectic liquid crystal (LC) phases using only the CG representation of BTBT. By bypassing the atomistic resolution and its prohibitive computational costs, ECG enables the first calculations of the morphology dependence of the electronic structure of charge carriers across LC phases at the ∼20 nm length scale, with robust statistical sampling. Kinetic Monte Carlo (kMC) simulations reveal a strong morphology dependence on zero-field charge mobility among different LC phases as well as the presence of two-molecule charge carriers that act as traps and hinder charge transport. We leverage these results to further evaluate the feasibility of developing mesoscopic, field-based ECG models in future works. The fully CG approach to electronic property predictions in LC semiconductors opens a new computational direction for designing electronic processes in soft materials at their characteristic length scales.
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Affiliation(s)
- Chun-I Wang
- Department of Chemistry, University of Illinois at Urbana-Champaign 505 S Mathews Avenue Urbana Illinois 61801 USA
| | - J Charlie Maier
- Department of Chemistry, University of Illinois at Urbana-Champaign 505 S Mathews Avenue Urbana Illinois 61801 USA
| | - Nicholas E Jackson
- Department of Chemistry, University of Illinois at Urbana-Champaign 505 S Mathews Avenue Urbana Illinois 61801 USA
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2
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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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3
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Ferrari E, Pandolfi L, Schweicher G, Geerts Y, Salzillo T, Masino M, Venuti E. Interlayer Sliding Phonon Drives Phase Transition in the Ph-BTBT-10 Organic Semiconductor. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2023; 35:5777-5783. [PMID: 37576586 PMCID: PMC10413852 DOI: 10.1021/acs.chemmater.3c00209] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/11/2023] [Indexed: 08/15/2023]
Abstract
In the field of organic electronics, the semiconductor 7-decyl-2-phenyl[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-10) has become a benchmark due to its high charge mobility and chemical stability in thin film devices. Its phase diagram is characterized by a crystal phase with a bilayer structure that at high temperature transforms into a Smectic E liquid crystal with monolayer structure. As the charge transport properties appear to depend on the phase present in the thin film, the transition has been the subject of structural and computational studies. Here such a process has been investigated by polarized low frequency Raman spectroscopy, selectively probing the intermolecular dynamics of the two phases. The spectroscopic observations demonstrate the key role played by a displacive component of the transition, with the interpenetration of the crystal bilayers driven by lattice phonon mode softening followed by the intralayer rearrangement of the molecule rigid cores into the herringbone motif of the liquid crystal. The mechanism can be related to the effectiveness of thermal annealing to restore the crystal phase in films.
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Affiliation(s)
- Elena Ferrari
- Dipartimento
di Scienze Chimiche, della Vita e della
Sostenibilità Ambientale & INSTM-UdR Parma, Parco Area delle Scienze, 17/A, Parma 43124, Italy
- IMEM-CNR, Parco Area delle Scienze, 37/A, Parma 43124, Italy
| | - Lorenzo Pandolfi
- Dipartimento
di Chimica Industriale “Toso Montanari” & INSTM-UdR
Bologna, Viale del Risorgimento 4, Bologna 40136, Italy
| | - Guillaume Schweicher
- Laboratoire
de Chimie des Polymères Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/01, Brussels 1050, Belgium
| | - Yves Geerts
- Laboratoire
de Chimie des Polymères Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, CP 206/01, Brussels 1050, Belgium
- International
Solvay Institutes of Physics and Chemistry Université Libre
de Bruxelles (ULB), Boulevard
du Triomphe, CP 206/01, Brussels 1050, Belgium
| | - Tommaso Salzillo
- Dipartimento
di Chimica Industriale “Toso Montanari” & INSTM-UdR
Bologna, Viale del Risorgimento 4, Bologna 40136, Italy
| | - Matteo Masino
- Dipartimento
di Scienze Chimiche, della Vita e della
Sostenibilità Ambientale & INSTM-UdR Parma, Parco Area delle Scienze, 17/A, Parma 43124, Italy
| | - Elisabetta Venuti
- Dipartimento
di Chimica Industriale “Toso Montanari” & INSTM-UdR
Bologna, Viale del Risorgimento 4, Bologna 40136, Italy
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4
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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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5
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Ebata K, Hashimoto Y, Ebara K, Tsukamoto M, Yamamoto S, Mitsuishi M, Nagano S, Matsui J. Molecular-weight dependence of the formation of highly ordered lamellar structures of poly(N-dodecyl acrylamide) by humid annealing. Polym Chem 2019. [DOI: 10.1039/c8py01660g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Highly oriented lamellar films of poly(N-dodecylacrylamide) with high molecular weights were formed by nanosegregation between alkyl side chains and a water-adsorbed main chain.
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Affiliation(s)
- Kazuki Ebata
- Graduate School of Science and Engineering
- Yamagata University
- Yamagata 990-8560
- Japan
| | - Yuki Hashimoto
- Graduate School of Science and Engineering
- Yamagata University
- Yamagata 990-8560
- Japan
| | - Kohei Ebara
- Faculty of Science
- Yamagata University
- Yamagata 990-8560
- Japan
| | - Mayu Tsukamoto
- Graduate School of Science and Engineering
- Yamagata University
- Yamagata 990-8560
- Japan
| | - Shunsuke Yamamoto
- Institute for Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Masaya Mitsuishi
- Institute for Multidisciplinary Research for Advanced Materials
- Tohoku University
- Sendai 980-8577
- Japan
| | - Shusaku Nagano
- Nagoya University Venture Business Laboratory
- Nagoya University
- Nagoya 464-8603
- Japan
| | - Jun Matsui
- Faculty of Science
- Yamagata University
- Yamagata 990-8560
- Japan
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6
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Yamamura Y, Murakoshi T, Iwagaki S, Osiecka N, Saitoh H, Hishida M, Galewski Z, Massalska-Arodź M, Saito K. Structure and molecular packing in smectic B Cr and A d phases of Schiff base liquid crystal compounds through the analyses of layer spacing, entropy and crystal structure. Phys Chem Chem Phys 2018; 19:19434-19441. [PMID: 28718465 DOI: 10.1039/c7cp03863a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Single-crystal structural analyses and heat capacity measurements were performed on two Schiff base liquid crystal compounds, 5CBAA (4-chlorobenzylidene-4'-pentyloxyaniline) and 5ABCA (4-pentyloxybenzylidene-4'-chloroaniline). The alkyloxy-chain of a 5CBAA molecule was conformationally ordered in the crystal at room temperature. While that of 5ABCA was partially disordered in the room temperature phase but ordered in a low-temperature phase at 100 K. The structural phase transition involving the disordering of the conformation was observed at 107 K in the heat capacity of 5ABCA. Both compounds showed two liquid crystalline phases, SmBCr and SmAd. The net entropy change associated with the chain disordering was essentially the same in them despite the difference in the orientation of their central -CH[double bond, length as m-dash]N- moiety. The layer-spacings of SmBCr and SmAd phases were analyzed for their chain-length dependence in both series of mesogens (nCBAA and nABCA), as well as in the case of nBBAA (4-bromobenzylidene-4'-alkyloxyaniline). The results reveal that these smectic structures are composed of alternately stacked core- and chain-layers with an antiparallel arrangement of cores and a bent-form of molecules.
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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
| | - Takahito Murakoshi
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Sakiko Iwagaki
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Natalia Osiecka
- The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Kraków 31-342, Poland
| | - Hideki Saitoh
- Department of Chemistry, Graduate School of Science and Engineering, Saitama University, Saitama 338-8570, Japan
| | - Mafumi Hishida
- 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
| | - Maria Massalska-Arodź
- The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Kraków 31-342, Poland
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
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7
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Yamamura Y, Murakoshi T, Hishida M, Saito K. Examination of molecular packing in orthogonal smectic liquid crystal phases: a guide for molecular design of functional smectic phases. Phys Chem Chem Phys 2017; 19:25518-25526. [PMID: 28900636 DOI: 10.1039/c7cp04744d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reported layer spacings (dsmectic) of six homologues of mesogens exhibiting orthogonal smectic phases (SmE, SmB, and SmA phases) are reexamined. The slopes of the linear dependences on chain length (n, the number of carbon atoms in the hydrocarbon chain) are clearly categorized into two groups: 1.9 Å (CH2)-1 and 1.4 Å (CH2)-1. It is clarified that in the former the molecules take a rod-like form (rod-form; category-I), whereas in the latter the molecules are bent around the connection between the core and chain moieties (bent-form; category-II). The average relative positions of adjacent molecules within the smectic structures are deduced from the intercept of the linear functions of dsmectic against n. The relation between and the features of molecules belonging to the two categories are discussed for molecular design of functional smectic liquid crystals.
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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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8
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Wu H, Iino H, Hanna JI. Thermally induced bilayered crystals in a solution-processed polycrystalline thin film of phenylterthiophene-based monoalkyl smectic liquid crystals and their effect on FET mobility. RSC Adv 2017. [DOI: 10.1039/c7ra11727b] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Herein, a series of asymmetric monoalkyl terthiophene derivatives, Ph-(Tp)3-Cn, (6 ≤ n ≤ 18), were synthesized to study the phase transition from monolayered crystal to bilayered crystal, leading to a significant increase of OFET mobility.
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Affiliation(s)
- Hao Wu
- Imaging Science and Engineering Research Center
- Tokyo Institute of Technology
- Midori-ku
- Japan
| | - Hiroaki Iino
- Imaging Science and Engineering Research Center
- Tokyo Institute of Technology
- Midori-ku
- Japan
| | - Jun-ichi Hanna
- Imaging Science and Engineering Research Center
- Tokyo Institute of Technology
- Midori-ku
- Japan
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9
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Usuda H, Hishida M, Yamamura Y, Saito K. Contrasting Effects of a Rigid Core and an Alkyl Chain in nCB on the Phase Behavior of Lipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5966-5972. [PMID: 27219128 DOI: 10.1021/acs.langmuir.6b00774] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Molecules incorporated into biomembranes often bear both a core and an alkyl chain in a single molecule (e.g., sterols). To clarify the effects of these two parts of a molecule, the phase behavior of a 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) bilayer containing 4-n-alkyl-4'-cyanobiphenyl (nCB) (n = 0-8) was investigated. The trends of the main transition temperature (Tm) with respect to n and of the pretransition temperature (Tp) with respect to nCB content changed at n = 3. It was therefore suggested that the two parts of the molecule had opposing effects on the phase behavior of DPPC bilayers. The core appears to perturb molecular ordering in the gel phase and lowers Tm (like cholesterol), while alkyl chains appear to order the lipids in the gel phase and raise Tm (like n-alkanes). In addition, Tm exhibits the so-called odd-even effect based on the alkyl chain length of the minor component, nCB. Depending on the value of n, the variation in Tp was dependent on the additive content, although the pretransition was rarely observed at high contents.
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Affiliation(s)
- Hatsuho Usuda
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
| | - Mafumi Hishida
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
| | - Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba , Tsukuba, Ibaraki 305-8571, Japan
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10
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Dryzek E, Juszyńska-Gałązka E. Positronium formation and annihilation in liquid crystalline smectic-E phase revisited. Phys Rev E 2016; 93:022705. [PMID: 26986386 DOI: 10.1103/physreve.93.022705] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Indexed: 11/07/2022]
Abstract
The results of the positron lifetime measurements of the quenched smectic-E (Sm-E) phase of 4-butyl-4'-isothiocyano-1,1'-biphenyl (4TCB) are revisited. The sites of positronium formation and annihilation, according to the model with nanosegregated layered structure of the Sm-E phase and molten state of alkyl chains of molecules, are identified in the sublayer containing alkyl chains of molecules. The possibility of vitrification of the Sm-E phase for 4TCB consisting in freezing of the alkyl chain motions is considered as a cause of the thermally activated creation of sites where o-Ps is formed and annihilates in the quenched Sm-E phase. The description of the temperature dependence of ortho-positronium intensity is performed using the glass transition model which assumes that the molecules occupy two thermodynamic states: solidlike or liquidlike regarding mobility of their alkyl chains. The equilibrium temperature between solidlike and liquidlike domains of the model obtained from positron lifetime measurements coincides with the exothermic effect in the temperature dependence of the heat capacity.
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Affiliation(s)
- E Dryzek
- Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Kraków, Poland
| | - E Juszyńska-Gałązka
- Institute of Nuclear Physics, Polish Academy of Sciences, ul. Radzikowskiego 152, 31-342 Kraków, Poland
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11
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Dutronc T, Terazzi E, Guénée L, Buchwalder KL, Floquet S, Piguet C. Chemical Programming of the Domain of Existence of Liquid Crystals. Chemistry 2015; 22:1385-91. [PMID: 26663074 DOI: 10.1002/chem.201503420] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Indexed: 11/11/2022]
Abstract
This work illustrates how enthalpy and entropy changes responsible for successive phase transitions of cyanobiphenyl-based liquid crystals can be combined to give cohesive free energy densities. These new parameters are able to rationalize and quantify the demixing of the melting and clearing processes that occur in thermotropic liquid crystals. Minor structural variations at the molecular level can be understood as pressure increments that alter either the melting or clearing temperatures in a predictable way. This assessment of microsegregation operating in amphiphilic molecules paves the way for the chemical programming of the domain of existence of liquid-crystalline phases.
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Affiliation(s)
- Thibault Dutronc
- Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, 1211, Geneva 4, Switzerland
| | - Emmanuel Terazzi
- Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, 1211, Geneva 4, Switzerland.
| | - Laure Guénée
- Laboratory of Crystallography, University of Geneva, 24 quai E. Ansermet, 1211, Geneva 4, Switzerland
| | - Kerry-Lee Buchwalder
- Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, 1211, Geneva 4, Switzerland
| | - Sébastien Floquet
- Institut Lavoisier de Versailles, UMR 8180, University of Versailles Saint-Quentin-en-Yvelines, 45 av. des Etats-Unis, 78035, Versailles, France
| | - Claude Piguet
- Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 quai E. Ansermet, 1211, Geneva 4, Switzerland.
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12
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Saito K, Hishida M, Yamamura Y. A possible critical point for nematic order on the basis of Landau free energy having dual instabilities for nano-segregated smectic liquid crystals. SOFT MATTER 2015; 11:8493-8498. [PMID: 26372214 DOI: 10.1039/c5sm02014j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Landau expansion of free energy assuming dual instabilities for the nano-segregated SmA phase is analyzed. In addition to known phase sequences (on cooling, disordered isotropic liquid → nematic phase → smectic phase, and disordered isotropic liquid → smectic phase), a new sequence (disordered isotropic liquid → density wave with subsidiary nematic order → smectic phase) and the existence of a critical point are demonstrated in the case where the instability for density wave formation occurs at a higher temperature.
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Affiliation(s)
- Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Mafumi Hishida
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
| | - Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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13
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Osiecka N, Massalska-Arodź M, Galewski Z, Chłędowska K, Bąk A. Effect of flip-flop motion on dielectric spectra of highly ordered liquid crystals. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:052503. [PMID: 26651713 DOI: 10.1103/physreve.92.052503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Indexed: 06/05/2023]
Abstract
This paper presents studies of dielectric response of chosen Schiff bases, which have similar molecular structures with different isomerizations of an azomethine bridging group, alkyloxy chain length with n=5 or n=6 carbon atoms, and a bromine or chlorine halogen terminal atom. Significant differences in the values of the maximum of dielectric absorption related to flip-flop molecular jumps in hexagonal smectic-B(Cry) phases have been found despite small differences of molecular dipole moments in these substances. This phenomenon is discussed in relation to the possibilities of the creation of dimers and to steric factors favoring motions.
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Affiliation(s)
- N Osiecka
- Department of Soft Matter Research, Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland
| | - M Massalska-Arodź
- Department of Soft Matter Research, Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland
| | - Z Galewski
- Faculty of Chemistry, University of Wrocław, Wrocław, Poland
| | - K Chłędowska
- Faculty of Mathematics and Applied Physics, Rzeszów University of Technology, Rzeszów, Poland
| | - A Bąk
- Faculty of Mathematics and Applied Physics, Rzeszów University of Technology, Rzeszów, Poland
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14
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Hishida M, Endo A, Nakazawa K, Yamamura Y, Saito K. Effect of n-alkanes on lipid bilayers depending on headgroups. Chem Phys Lipids 2015; 188:61-7. [PMID: 25957868 DOI: 10.1016/j.chemphyslip.2015.05.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 04/28/2015] [Accepted: 05/04/2015] [Indexed: 10/23/2022]
Abstract
Phase behavior and structural properties were examined for phospholipid bilayers having different headgroups (DMPC, DMPS and DMPE) with added n-alkanes to study effect of flexible additives. Change in the temperatures of main transition of the lipid/alkane mixtures against the length of added alkanes depends largely on the headgroup. Theoretical analysis of the change of the temperature of transition indicates that the headgroup dependence is dominantly originated in the strong dependence of total enthalpy on the headgroups. The results of X-ray diffraction show that the enthalpic stabilization due to enhanced packing of acyl chains of the lipid by alkanes in the gel phase causes the headgroup-dependent change in the phase transition behavior. The enhanced packing in the gel phase also leads to easy emergence of the subgel phase with very short relaxation time at room temperature in the DMPE-based bilayers.
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Affiliation(s)
- Mafumi Hishida
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Asami Endo
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Koyomi Nakazawa
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Yasuhisa Yamamura
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan
| | - Kazuya Saito
- Department of Chemistry, Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan.
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Park S, Ryu MH, Shin TJ, Cho BK. Smectic assemblies in C₃-symmetric hexa-alkylated liquid crystals: transformation from smectogen to discogen via hydrogen bonding. SOFT MATTER 2014; 10:5804-5809. [PMID: 24975589 DOI: 10.1039/c4sm00919c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this paper, we report a C3-symmetric liquid crystal (LC) with sixfold alkyl peripheries exhibiting an unusual smectic E-like organization in the LC state. Based on conformational considerations, the smectic assembly is attributed to the formation of an endo-type Y conformer of asymmetric triazolyl and benzylic groups that cannot be accessed in other C3-symmetric molecules exclusively showing columnar assemblies. The Y conformers form a two-dimensional oblique lattice in the aromatic layers of the ordered smectic phase. In addition, the Y-shaped molecule in the smectic phases can change into a circular shape by the 1 : 1 hydrogen-bonding interaction with a gallic acid derivative, which leads to a hexagonal columnar LC phase. The triazole-based LC design concept proves the smectic LC assembly in the C3-symmetric system, and provides the supramolecular manipulation of LC morphologies.
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Affiliation(s)
- Soyoung Park
- Department of Chemistry and Institute of Nanosensor and Biotechnology, Dankook University, Gyeonggi-Do 448-701, Korea.
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