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Lamellar Tetragonal Symmetry of Amphiphilic Thermotropic Ionic Liquid Crystals in the Framework of Other Closely Related Highly Ordered Structures. Symmetry (Basel) 2022. [DOI: 10.3390/sym14020394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022] Open
Abstract
An overview of the chemical compounds forming the rare smectic T phases is presented with references to the historical context. Thermodynamics (transition temperatures, enthalpies) along with the factors (stereochemical constraints, electrostatic interactions, aliphatic chain stacking, intermolecular forces) contributing to the adoption of tetragonal scaffolds are also discussed. Characteristic optical microscopy textures and X-ray diffraction patterns are presented. In parallel, a comparison of the geometrical parameters such as distances between atoms, molecular areas, volumes, and lattice parameters with the closest two-dimensional and three-dimensional organizations, is performed.
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Cao W, Senthilkumar B, Causin V, Swamy VP, Wang Y, Saielli G. Influence of the ion size on the stability of the smectic phase of ionic liquid crystals. SOFT MATTER 2020; 16:411-420. [PMID: 31789337 DOI: 10.1039/c9sm02115a] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The thermotropic phase behavior of ionic liquids and ionic liquid crystals based on novel N-alkyl-3-methylpyridinium halides, trihalides and dichloroiodates was experimentally studied by polarized optical spectroscopy (POM) and differential scanning calorimetry (DSC) as well as by molecular dynamics (MD) simulation. In the experiments, the existence and thermal range of stability of the smectic phase of these ionic liquid crystals are found to strongly depend on the volume ratio between the cation and anion, that is their relative size. Only compounds with a relatively large volume ratio of the cation to anion, i.e., those with longer cationic alkyl chains and monoatomic halide anions, have a stable smectic A phase. Both melting points and clearing points increase with such a ratio. The MD simulation results qualitatively agree very well with the experimental data and provide molecular details which can explain the experimentally observed phenomena: the stronger van der Waals interactions from the longer alkyl chains and the stronger electrostatic interactions from the smaller anions with a higher charge density increase the stability of both the crystal phase and the smectic phase; this also prevents the ionic layers from easily mixing with the hydrophobic regions, a mechanism that ultimately leads to a nanosegregated isotropic liquid phase.
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Affiliation(s)
- Wudi Cao
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, 55 East Zhongguancun Road, P. O. Box 2735, Beijing 100190, China.
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Park G, Goossens K, Shin TJ, Bielawski CW. Dicyanamide Salts that Adopt Smectic, Columnar, or Bicontinuous Cubic Liquid-Crystalline Mesophases. Chemistry 2018; 24:6399-6411. [PMID: 29446859 DOI: 10.1002/chem.201705794] [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: 12/07/2017] [Indexed: 01/19/2023]
Abstract
Although dicyanamide (i.e., [N(CN)2 ]- ) has been commonly used to obtain low-viscosity, halogen-free, room-temperature ionic liquids, liquid-crystalline salts containing such anions have remained virtually unexplored. Here we report a series of amphiphilic dicyanamide salts that, depending on their structures and compositions, adopt smectic, columnar, or bicontinuous cubic thermotropic liquid-crystalline mesophases, even at room temperature in some cases. Their thermal properties were explored by polarized light optical microscopy, differential scanning calorimetry, thermogravimetric analysis (including evolved gas analysis), and variable-temperature synchrotron X-ray diffraction. Comparison of the thermal phase characteristics of these new liquid-crystalline salts featuring "V-shaped" [N(CN)2 ]- anions with those of structural analogues containing [SCN]- , [BF4 ]- , [PF6 ]- , or [CF3 SO3 ]- anions indicated that not only the size of the counterion but also its shape should be considered in the development of mesomorphic salts. Collectively, these discoveries may be expected to facilitate the design of thermotropic ionic liquid crystals that form inverted-type bicontinuous cubic and other sophisticated liquid-crystalline phases.
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Affiliation(s)
- Geonhui Park
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.,Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Karel Goossens
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Tae Joo Shin
- UNIST Central Research Facilities (UCRF) and School of Natural Science, UNIST, Ulsan, 44919, Republic of Korea
| | - Christopher W Bielawski
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.,Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.,Department of Energy Engineering, UNIST, Ulsan, 44919, Republic of Korea
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4
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Peng H, Kubo M, Shiba H. Molecular dynamics study of mesophase transitions upon annealing of imidazolium-based ionic liquids with long-alkyl chains. Phys Chem Chem Phys 2018; 20:9796-9805. [PMID: 29620128 DOI: 10.1039/c8cp00698a] [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
Molecular dynamics simulations are performed on a 1-dodecyl-3-methylimidazolium hexafluorophosphate ([C12mim][PF6]) ionic liquid using a united-atom model. The ionic liquid exhibits second step relaxation at temperatures below a crossover point, where the diffusion coefficient shows an Arrhenius to non-Arrhenius transition. Annealing below this crossover temperature makes an isotropic to mesophase transition, where the smectic A (SmA) phase or crystal-like smectic B (SmB) phase forms. Hundreds of nanoseconds are required for completing these transitions. A normal diffusion process is found for anions along the layer-normal and -lateral directions in the SmA phase, but only in the lateral directions in the SmB phase. We find a preserved orientational order for the imidazolium-ring rotational and the alkyl-chain reorientational dynamics in both of the smectic phases.
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Affiliation(s)
- Hailong Peng
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
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Zama I, Gorni G, Borzatta V, Cassani MC, Crupi C, Di Marco G. Fluorinated imidazolium salts having liquid crystal characteristics. J Mol Liq 2016. [DOI: 10.1016/j.molliq.2016.08.101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Goossens K, Lava K, Bielawski CW, Binnemans K. Ionic Liquid Crystals: Versatile Materials. Chem Rev 2016; 116:4643-807. [PMID: 27088310 DOI: 10.1021/cr400334b] [Citation(s) in RCA: 411] [Impact Index Per Article: 51.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the "state-of-the-art" in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.
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Affiliation(s)
- Karel Goossens
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea.,Department of Chemistry, KU Leuven , Celestijnenlaan 200F, P.O. Box 2404, B-3001 Heverlee, Belgium
| | - Kathleen Lava
- Department of Chemistry, KU Leuven , Celestijnenlaan 200F, P.O. Box 2404, B-3001 Heverlee, Belgium.,Department of Organic and Macromolecular Chemistry, Ghent University , Krijgslaan 281 S4, B-9000 Ghent, Belgium
| | - Christopher W Bielawski
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS) , Ulsan 689-798, Republic of Korea.,Department of Chemistry and Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Republic of Korea
| | - Koen Binnemans
- Department of Chemistry, KU Leuven , Celestijnenlaan 200F, P.O. Box 2404, B-3001 Heverlee, Belgium
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Saielli G. Fully Atomistic Simulations of the Ionic Liquid Crystal [C16mim][NO3]: Orientational Order Parameters and Voids Distribution. J Phys Chem B 2016; 120:2569-77. [DOI: 10.1021/acs.jpcb.5b12469] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Giacomo Saielli
- CNR Institute
on Membrane
Technology and Department of Chemical Sciences, University of Padova, Via Marzolo, 1, 35131 Padova, Italy
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8
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Ionic conductivities of N-decyl-n-methylprrolidinium. ELECTROCHEMISTRY 2016. [DOI: 10.1007/978-3-642-02723-9_404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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9
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Holze R. Ionic conductivities of N-tetradecyl-n-methylprrolidinium. ELECTROCHEMISTRY 2016. [DOI: 10.1007/978-3-642-02723-9_408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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10
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Ionic conductivities of N-dodecyl-n-methylprrolidinium. ELECTROCHEMISTRY 2016. [DOI: 10.1007/978-3-642-02723-9_406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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Luo J, Lu J, Zhao D, Du X, He X, Meng F. Imidazolium-based polymerized ionic liquid crystals containing fluorinated cholesteryl mesogens. POLYM ADVAN TECHNOL 2015. [DOI: 10.1002/pat.3634] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jingqi Luo
- College of Science; Northeastern University; Shenyang 100819 China
| | - Jinmin Lu
- College of Science; Northeastern University; Shenyang 100819 China
| | - Dongyu Zhao
- College of Science; Northeastern University; Shenyang 100819 China
| | - Xinyu Du
- College of Science; Northeastern University; Shenyang 100819 China
| | - Xiaozhi He
- College of Science; Northeastern University; Shenyang 100819 China
| | - Fanbao Meng
- College of Science; Northeastern University; Shenyang 100819 China
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Ma S, Li X, Bai L, Lan X, Zhou N, Meng F. Synthesis and characterization of imidazolium-based polymerized ionic liquid crystals containing cholesteryl mesogens. Colloid Polym Sci 2015. [DOI: 10.1007/s00396-015-3617-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Lan X, Bai L, Li X, Ma S, He X, Meng F. Cholesteryl-containing ionic liquid crystals composed of alkylimidazolium cations and different anions. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2014.07.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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Xu F, Matsumoto K, Hagiwara R. Phase Behavior of 1-Dodecyl-3-methylimidazolium Fluorohydrogenate Salts (C12MIm(FH)nF, n = 1.0–2.3) and Their Anisotropic Ionic Conductivity as Ionic Liquid Crystal Electrolytes. J Phys Chem B 2012; 116:10106-12. [DOI: 10.1021/jp305228u] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fei Xu
- Graduate
School of Energy Science, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhiko Matsumoto
- Graduate
School of Energy Science, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
| | - Rika Hagiwara
- Graduate
School of Energy Science, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan
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