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Chen D, Coleman DA, Zhu C, Chattham N, Jenz F, Cheng X, Tschierske C, Glaser MA, Maclennan JE, Clark NA. Frustration between two- and three-dimensional smectic ordering leads to a biaxial nematic phase. SOFT MATTER 2020; 16:747-753. [PMID: 31825443 DOI: 10.1039/c9sm01809c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The bola-amphiphilic, T-shaped mesogen CT2 has an aromatic, biphenyl core terminated on both ends by hydrophilic groups and a semi-perfluorinated, aliphatic side chain. Upon cooling from the isotropic phase, the fluorinated tails and the polar, rod-like cores nanophase-segregate to form a fluid lamellar phase. At high temperatures, the biphenyl cores are orientationally disordered in two dimensions (2D) in the lamellar planes but on further cooling the cores order orientationally, giving a biaxial lamellar phase with 2D nematic in-plane ordering. At lower temperature, the aromatic and hydrophilic parts of the cores nanosegregate within the lamellae and 2D smectic correlations of the head groups develop. X-ray diffraction shows that this 2D smectic ordering is incompatible with the initial lamellar structure, with both structures becoming short-ranged, resulting in a 3D biaxial nematic phase with macroscopic orthorhombic symmetry featuring strong smectic correlations in two orthogonal spatial dimensions. Freeze-fracture transmission electron microscopy enables direct visualization of the resulting short-ranged periodic structures.
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Affiliation(s)
- Dong Chen
- Institute of Process Equipment, College of Energy Engineering, Zhejiang University, Zheda Road No. 38, Hangzhou, 310027, China
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2
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Prehm M, Enders C, Mang X, Zeng X, Liu F, Ungar G, Baumeister U, Tschierske C. Lamellar Liquid Crystals of In-Plane Lying Rod-Like Mesogens with Designer Side-Chains: The Case of Sliding versus Locked Layers. Chemistry 2018; 24:16072-16084. [PMID: 29939440 DOI: 10.1002/chem.201802050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Indexed: 12/30/2022]
Abstract
The dimensionality of self-assembled nanostructures plays an essential role for their properties and applications. Herein, an understanding of the transition from weakly to strongly coupled layers in soft matter systems is provided involving in-plane organized π-conjugated rods. For this purpose, bolaamphiphilic triblock molecules consisting of a rigid biphenyl core, polar glycerol groups at the ends, and a branched (swallow-tail) or linear alkyl or semiperfluoroalkyl chain in lateral position have been synthesized and investigated. Besides weakly coupled lamellar isotropic (LamIso ), lamellar nematic (LamN ) and sliding lamellar smectic phases (LamSm ), a sequence of three distinct types of strongly coupled (correlated) lamellar smectic phases with either centered (c2mm) or non-centered rectangular (p2mm) lattice and an intermediate oblique lattices (p2) were observed depending on chain length, chain branching and degree of chain fluorination. This new sequence is explained by the strengthening of the layer coupling and the competition between energetic packing constraints and the entropic contribution of either longitudinal or tangential fluctuations. This example of directed side chain engineering of small generic model compounds provides general clues for morphological design of two-dimensional and three-dimensionally coupled lamellar systems involving larger π-conjugated molecular rods and molecular or supramolecular polymers, being of actual interest in organic electronics and nanotechnology.
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Affiliation(s)
- Marko Prehm
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str.2, 06120, Halle, Germany
| | - Claudia Enders
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str.2, 06120, Halle, Germany
| | - Xiaobin Mang
- Department of Engineering Materials, University of Sheffield, Robert Hadfield Building Mappin Street, Sheffield, S1 3JD, UK
| | - Xiangbing Zeng
- Department of Engineering Materials, University of Sheffield, Robert Hadfield Building Mappin Street, Sheffield, S1 3JD, UK
| | - Feng Liu
- State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, 710049, P. R. China
| | - Goran Ungar
- Department of Engineering Materials, University of Sheffield, Robert Hadfield Building Mappin Street, Sheffield, S1 3JD, UK.,Department of Physics, Zhejiang Sci-Tech University, Xiasha College Park, Hangzhou, 310018, P. R. China
| | - Ute Baumeister
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str.2, 06120, Halle, Germany
| | - Carsten Tschierske
- Institute of Chemistry, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str.2, 06120, Halle, Germany
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Tschierske C. Entwicklung struktureller Komplexität durch Selbstorganisation in flüssigkristallinen Systemen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201300872] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Tschierske C. Development of structural complexity by liquid-crystal self-assembly. Angew Chem Int Ed Engl 2013; 52:8828-78. [PMID: 23934786 DOI: 10.1002/anie.201300872] [Citation(s) in RCA: 354] [Impact Index Per Article: 32.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Indexed: 11/09/2022]
Abstract
Since the discovery of the liquid-crystalline state of matter 125 years ago, this field has developed into a scientific area with many facets. This Review presents recent developments in the molecular design and self-assembly of liquid crystals. The focus is on new exciting soft-matter structures distinct from the usually observed nematic, smectic, and columnar phases. These new structures have enhanced complexity, including multicompartment and cellular structures, periodic and quasiperiodic arrays of spheres, and new emergent properties, such as ferroelctricity and spontaneous achiral symmetry-breaking. Comparisons are made with developments in related fields, such as self-assembled monolayers, multiblock copolymers, and nanoparticle arrays. Measures of structural complexity used herein are the size of the lattice, the number of distinct compartments, the dimensionality, and the logic depth of the resulting supramolecular structures.
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Affiliation(s)
- Carsten Tschierske
- Institut für Chemie, Organische Chemie, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle Saale, Germany.
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Paczesny J, Sozański K, Żywociński A, Hołyst R, Glettner B, Kieffer R, Tschierske C, Nikiforov K, Pociecha D, Górecka E. Spontaneous self-assembly of partially fluorinated bolaamphiphiles into ordered layered structures. Phys Chem Chem Phys 2012; 14:14365-73. [DOI: 10.1039/c2cp41970j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Tschierske C, Nürnberger C, Ebert H, Glettner B, Prehm M, Liu F, Zeng XB, Ungar G. Complex tiling patterns in liquid crystals. Interface Focus 2011; 2:669-80. [PMID: 24098852 DOI: 10.1098/rsfs.2011.0087] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Accepted: 11/22/2011] [Indexed: 11/12/2022] Open
Abstract
In this account recent progress in enhancing the complexity of liquid crystal self-assembly is highlighted. The discussed superstructures are formed mainly by polyphilic T-shaped and X-shaped molecules composed of a rod-like core, tethered with glycerol units at both ends and flexible non-polar chain(s) in lateral position, but also related inverted molecular structures are considered. A series of honeycomb phases composed of polygonal cylinders ranging from triangular to hexagonal, followed by giant cylinder honeycombs is observed for ternary T-shaped polyphiles on increasing the size of the lateral chain(s). Increasing the chain size further leads to new modes of lamellar organization followed by three-dimensional and two-dimensional structures incorporating branched and non-branched axial rod-bundles. Grafting incompatible chains to opposite sides of the rod-like core leads to quaternary X-shaped polyphiles. These form liquid crystalline honeycombs where different cells are filled with different material. Projected on an Euclidian plane, all honeycomb phases can be described either by uniformly coloured Archimedean and Laves tiling patterns (T-shaped polyphiles) or as multi-colour tiling patterns (X-shaped polyphiles). It is shown that geometric frustration, combined with the tendency to segregate incompatible chains into different compartments and the need to find a periodic tiling pattern, leads to a significant increase in the complexity of soft self-assembly. Mixing of different chains greatly enhances the number of possible 'colours' and in this way, periodic structures comprising up to seven distinct compartments can be generated. Relations to biological self-assembly are discussed shortly.
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Affiliation(s)
- C Tschierske
- Institute of Chemistry, Organic Chemistry , Martin-Luther University Halle-Wittenberg , Kurt-Mothes Strasse 2, 06120 Halle/Saale , Germany
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Cheng X, Liu F, Zeng X, Ungar G, Kain J, Diele S, Prehm M, Tschierske C. Influence of Flexible Spacers on Liquid-Crystalline Self-Assembly of T-Shaped Bolaamphiphiles. J Am Chem Soc 2011; 133:7872-81. [DOI: 10.1021/ja200822z] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xiaohong Cheng
- Department of Chemistry, Key Laboratory of Medicinal Chemistry for Natural Resources (Ministry of Education), Yunnan University, Kunming, Yunnan 650091, P. R. China
| | - Feng Liu
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S13JD, U.K
| | - Xiangbing Zeng
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S13JD, U.K
| | - Goran Ungar
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S13JD, U.K
- WCU program Chemical Convergence for Energy and Environment, School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea
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Nitoń P, Żywociński A, Paczesny J, Fiałkowski M, Hołyst R, Glettner B, Kieffer R, Tschierske C, Pociecha D, Górecka E. Aggregation and Layering Transitions in Thin Films of X-, T-, and Anchor-Shaped Bolaamphiphiles at the Air-Water Interface. Chemistry 2011; 17:5861-73. [DOI: 10.1002/chem.201003671] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Indexed: 12/19/2022]
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Prehm M, Liu F, Zeng X, Ungar G, Tschierske C. Axial-Bundle Phases − New Modes of 2D, 3D, and Helical Columnar Self-Assembly in Liquid Crystalline Phases of Bolaamphiphiles with Swallow Tail Lateral Chains. J Am Chem Soc 2011; 133:4906-16. [DOI: 10.1021/ja110065r] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Marko Prehm
- Organic Chemistry, Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 2, D-06120 Halle, Germany
| | - Feng Liu
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S13JD, United Kingdom
| | - Xiangbing Zeng
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S13JD, United Kingdom
| | - Goran Ungar
- Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S13JD, United Kingdom
- WCU Program Chemical Convergence for Energy & Environment, School of Chemical and Biological Engineering, Seoul National University, Seoul, Korea
| | - Carsten Tschierske
- Organic Chemistry, Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Strasse 2, D-06120 Halle, Germany
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Tschierske C. Fluorinated Liquid Crystals: Design of Soft Nanostructures and Increased Complexity of Self-Assembly by Perfluorinated Segments. Top Curr Chem (Cham) 2011; 318:1-108. [DOI: 10.1007/128_2011_267] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Prehm M, Enders C, Anzahaee M, Glettner B, Baumeister U, Tschierske C. Distinct Columnar and Lamellar Liquid Crystalline Phases Formed by New Bolaamphiphiles with Linear and Branched Lateral Hydrocarbon Chains. Chemistry 2008; 14:6352-68. [DOI: 10.1002/chem.200800141] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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12
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Kieffer R, Prehm M, Glettner B, Pelz K, Baumeister U, Liu F, Zeng X, Ungar G, Tschierske C. X-Shaped polyphilics: liquid crystal honeycombs with single-molecule walls. Chem Commun (Camb) 2008:3861-3. [DOI: 10.1039/b804945a] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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13
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Prehm M, Liu F, Baumeister U, Zeng X, Ungar G, Tschierske C. The Giant-Hexagon Cylinder Network—A Liquid-Crystalline Organization Formed by a T-Shaped Quaternary Amphiphile. Angew Chem Int Ed Engl 2007; 46:7972-5. [PMID: 17786908 DOI: 10.1002/anie.200703171] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Marko Prehm
- Institut für Chemie, Organische Chemie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Strasse 2, 06120 Halle, Germany
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Prehm M, Liu F, Baumeister U, Zeng X, Ungar G, Tschierske C. The Giant-Hexagon Cylinder Network—A Liquid-Crystalline Organization Formed by a T-Shaped Quaternary Amphiphile. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200703171] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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15
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Tschierske C. Liquid crystal engineering – new complex mesophase structures and their relations to polymer morphologies, nanoscale patterning and crystal engineering. Chem Soc Rev 2007; 36:1930-70. [DOI: 10.1039/b615517k] [Citation(s) in RCA: 414] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Chen B, Baumeister U, Pelzl G, Das MK, Zeng X, Ungar G, Tschierske C. Carbohydrate rod conjugates: ternary rod-coil molecules forming complex liquid crystal structures. J Am Chem Soc 2006; 127:16578-91. [PMID: 16305247 DOI: 10.1021/ja0535357] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
T-shaped polyphilic triblock molecules, consisting of a rodlike p-terphenyl unit, a hydrophilic and flexible laterally attached oligo(oxyethylene) chain terminated by an 1-acylamino-1-deoxy-D-sorbitol unit, and two end-attached lipophilic alkyl chains, have been synthesized by palladium-catalyzed cross-coupling reactions as the key steps. The thermotropic liquid crystalline behavior of these compounds was investigated by polarized light microscopy, differential scanning calorimetry (DSC), and X-ray scattering. We investigated the mode of self-organization as a function of the length and position of the lateral polar chain and the length of the terminal alkyl chains. Depending on the size of the polar and lipophilic segments, a series of unusual liquid crystalline phases was detected. In three of these phases, the space is divided into three distinct periodic subspaces. In addition to a hexagonal channeled layer phase (ChL(hex)) consisting of layers that are penetrated by polar columns, there are also two honeycomb-like network structures formed by square (Col(squ)/p4mm) or pentagonal cylinders (Col(squ)/p4gm). The cylinder walls consist of the terphenyl units fused by columns of alkyl chains, and the interior contains the polar side chains. In addition, a hexagonal columnar phase was observed in which the polar columns are organized in a continuum of terphenyls and alkyl chains with an organization of the terphenyl cores tangentially around the columns with the long axis perpendicular to the columns. For one compound, a reversal of birefringence was observed, which is explained by a reorientation of the terphenyl cores. The addition of protic solvents induces lamellar phases.
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Affiliation(s)
- Bin Chen
- Institute of Organic Chemistry, University Halle, Kurt-Mothes-Strasse 2, D-06120 Halle, Germany
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Huang F, Banfield JF. Size-Dependent Phase Transformation Kinetics in Nanocrystalline ZnS. J Am Chem Soc 2005; 127:4523-9. [PMID: 15783236 DOI: 10.1021/ja048121c] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nanocrystalline ZnS was coarsened under hydrothermal conditions to investigate the effect of particle size on phase transformation kinetics. Although bulk wurtzite is metastable relative to sphalerite below 1020 degrees C at low pressure, sphalerite transforms to wurtzite at 225 degrees C in the hydrothermal experiments. This indicates that nanocrystalline wurtzite is stable at low temperature. High-resolution transmission electron microscope data indicate there are no pure wurtzite particles in the coarsened samples and that wurtzite only grows on the surface of coarsened sphalerite particles. Crystal growth of wurtzite stops when the diameter of the sphalerite-wurtzite interface reaches approximately 22 nm. We infer that crystal growth of wurtzite is kinetically controlled by the radius of the sphalerite-wurtzite interface. A new phase transformation kinetic model based on collective movement of atoms across the interface is developed to explain the experimental results.
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Affiliation(s)
- Feng Huang
- Department of Earth and Planetary Science, University of California, Berkeley, California 94720-4767, USA.
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Cook AG, Baumeister U, Tschierske C. Supramolecular dendrimers: Unusual mesophases of ionic liquid crystals derived from protonation of DAB dendrimers with facial amphiphilic carboxylic acids. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b415892j] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hegmann T, Neumann B, Wolf R, Tschierske C. Liquid crystalline paracyclophanes and ansa compounds—series of polyether macrocycles incorporating diacetylene, phenyl, biphenyl, p-terphenyl and 2,5-diphenyl-1,3,4-thiadiazole rigid cores. ACTA ACUST UNITED AC 2005. [DOI: 10.1039/b416091f] [Citation(s) in RCA: 30] [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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20
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Cheng X, Das MK, Baumeister U, Diele S, Tschierske C. Liquid Crystalline Bolaamphiphiles with Semiperfluorinated Lateral Chains: Competition between Layerlike and Honeycomb-Like Organization. J Am Chem Soc 2004; 126:12930-40. [PMID: 15469290 DOI: 10.1021/ja048224v] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Novel bolaamphiphilic triblockmolecules consisting of a rigid biphenyl unit, with a polar 2,3-dihydroxypropyloxy group and a phenolic OH group at opposite ends, as well as a semiperfluorinated chain in a lateral position have been synthesized via palladium catalyzed cross coupling reactions as the key steps. The thermotropic liquid crystalline behavior of these compounds was investigated by polarized light microscopy, DSC and X-ray scattering, and the influence of the length of the lateral chain on the mesomorphic properties was studied. The compound with the shortest chain as well as the long chain derivatives form lamellar mesophases composed of segregated layers of the bolaamphiphilic moieties and sublayers comprising the fluid lateral chains. The layers within the lamellar phases of the short chain compound adopt a positional correlation, leading to a 2D lattice (Col(r)/p2mm), whereas the layers of the lamellar phases of the long chain derivatives are noncorrelated (Lam). Compounds with a medium chain length organize into columnar phases, where the nonpolar lateral chains segregate into columns, which are embedded in networks of regular (Col(h)) or stretched (Col(r)/c2mm) hexagonal cylinder shells consisting of the bolaamphiphilic units. In total, an unusual phase sequence was found, where, with respect to the chain length, columnar mesophases occur between two mesophases with layer organization.
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Affiliation(s)
- Xiaohong Cheng
- Contribution from the Institute of Organic Chemistry, University Halle, Kurt-Mothes-Strasse 2, D-06120 Halle, Germany
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