scholarly journals Ion conformation and orientational order in a dicationic ionic liquid crystal studied by solid-state nuclear magnetic resonance spectroscopy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Debashis Majhi ◽  
Sergey V. Dvinskikh
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Crystals ◽  
Bond Order ◽  
Van Der Waals ◽  
Orientational Order ◽  
Smectic Phase ◽  
Side Chains ◽  
Dicationic Ionic Liquid ◽  
Ionic Liquid Crystals

AbstractIonic liquids crystals belong to a special class of ionic liquids that exhibit thermotropic liquid-crystalline behavior. Recently, dicationic ionic liquid crystals have been reported with a cation containing two single-charged ions covalently linked by a spacer. In ionic liquid crystals, electrostatic and hydrogen bonding interactions in ionic sublayer and van der Waals interaction in hydrophobic domains are the main forces contributing to the mesophase stabilization and determining the molecular orientational order and conformation. How these properties in dicationic materials are compared to those in conventional monocationic analogs? We address this question using a combination of advanced NMR methods and DFT analysis. Dicationic salt 3,3′-(1,6-hexanediyl)bis(1-dodecylimidazolium)dibromide was studied. Local bond order parameters of flexible alkyl side chains, linker chain, and alignment of rigid polar groups were analyzed. The dynamic spacer effectively “decouples” the motion of two ionic moieties. Hence, local order and alignment in dicationic mesophase were similar to those in analogous single-chain monocationic salts. Bond order parameters in the side chains in the dicationic smectic phase were found consistently lower compared to double-chain monocationic analogs, suggesting decreasing contribution of van der Waals forces. Overall dication reorientation in the smectic phase was characterized by low values of orientational order parameter S. With increased interaction energy in the polar domain the layered structure is stabilized despite less ordered dications. The results emphasized the trends in the orientational order in ionic liquid crystals and contributed to a better understanding of interparticle interactions driving smectic assembly in this and analogous ionic mesogens.

scholarly journals Designing Functional Polyoxometalate-Based Ionic Liquid Crystals and Ionic Liquids

2019 ◽  
Vol 2020 (3) ◽  
pp. 228-247 ◽  
Author(s):  
Yohan Martinetto ◽  
Bruce Pégot ◽  
Catherine Roch-Marchal ◽  
Betty Cottyn-Boitte ◽  
Sébastien Floquet
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Crystals ◽  
Ionic Liquid Crystals

scholarly journals Ionic Liquid Crystals in Tribology

Lubricants ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 72 ◽  
Author(s):  
M.D. Avilés ◽  
C. Sánchez ◽  
R. Pamies ◽  
J. Sanes ◽  
M.D. Bermúdez
Keyword(s):  
Molecular Structure ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Crystals ◽  
Tribological Performance ◽  
Wear Rates ◽  
Fatty Acid Derivatives ◽  
Potential Applications ◽  
Ionic Liquid Crystals ◽  
Definition Of

The present work intends to provide a brief account of the most recent advances in the use of ionic liquid crystals (ILCs) in the field of tribology, that is, the development of new lubricants with the ability to reduce the coefficients of friction and the wear rates of materials under sliding conditions. After a definition of ILCs and their relationship with neutral liquid crystals (LCs) and ionic liquids (ILs), the review will be focused on the influence of molecular structure and composition on the tribological performance, the combination with base oils, surfactants or water, and the different sliding configuration and potential applications. The main mechanisms proposed in order to justify the lubricating ability of ILCs will be analyzed. Special emphasis will be made for recent results obtained for fatty acid derivatives due to their renewable and environmentally friendly nature.

scholarly journals 2D assemblies of ionic liquid crystals based on imidazolium moieties: formation of ion-conductive layers

2015 ◽  
Vol 39 (6) ◽  
pp. 4471-4477 ◽  
Author(s):  
Junji Sakuda ◽  
Masafumi Yoshio ◽  
Takahiro Ichikawa ◽  
Hiroyuki Ohno ◽  
Takashi Kato
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Crystals ◽  
Ionic Conductivity ◽  
Imidazolium Ionic Liquids ◽  
Ionic Liquid Crystals

Organization of imidazolium ionic liquids into 2D ion-conductive pathways enhances the ionic conductivity of the imidazolium-based ionic liquid crystals.

Ionic liquids and ionic liquid crystals of vinyl functionalized imidazolium salts

2011 ◽  
Vol 21 (6) ◽  
pp. 1866-1873 ◽  
Author(s):  
Shih-Ci Luo ◽  
Shaowen Sun ◽  
Amol R. Deorukhkar ◽  
Jung-Tang Lu ◽  
Amitabha Bhattacharyya ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Crystals ◽  
Imidazolium Salts ◽  
Ionic Liquid Crystals

scholarly journals NMR Spectroscopic Studies of Cation Dynamics in Symmetrically-Substituted Imidazolium-Based Ionic Liquid Crystals

2020 ◽  
Vol 21 (14) ◽  
pp. 5024
Author(s):  
Debashis Majhi ◽  
Andrei V. Komolkin ◽  
Sergey V. Dvinskikh
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Orientational Order ◽  
Soft Materials ◽  
Spectroscopic Studies ◽  
Single Chain ◽  
Self Assembling ◽  
Ionic Liquid Crystals ◽  
Cation Size

Ionic liquid crystals (ILCs) present a new class of non-molecular soft materials with a unique combination of high ionic conductivity and anisotropy of physicochemical properties. Symmetrically-substituted long-chain imidazolium-based mesogenic ionic liquids exhibiting a smectic liquid crystalline phase were investigated by solid state NMR spectroscopy and computational methods. The aim of the study was to reveal the correlation between cation size and structure, local dynamics, and orientational order in the layered mesophase. The obtained experimental data are consistent with the model of a rod-shaped cation with the two chains aligned in opposite directions outward from the imidazolium core. The alignment of the core plane to the phase director and the restricted conformations of the chain segments were determined and compared to those in single-chain counterparts. The orientational order parameter S~0.5–0.6 of double-chain ionic liquid crystals is higher than that of corresponding single-chain analogues. This is compatible with the enhanced contribution of van der Waals forces to the stabilization of smectic layers. Increased orientational order for the material with Br− counterions, which exhibit a smaller ionic radius and higher ability to form hydrogen bonds as compared to that of BF4−, also indicated a non-negligible influence of electrostatic and hydrogen bonding interactions. The enhanced rod-shape character and higher orientational order of symmetrically-substituted ILCs can offer additional opportunities in the design of self-assembling non-molecular materials.

scholarly journals NMR Spectroscopic Study of Orientational Order in Imidazolium-Based Ionic Liquid Crystals

Crystals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 495 ◽  
Author(s):  
Jing Dai ◽  
Debashis Majhi ◽  
Boris B. Kharkov ◽  
Sergey V. Dvinskikh
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Structural Model ◽  
Orientational Order ◽  
Smectic Layer ◽  
Charge Delocalization ◽  
Smectic A ◽  
Counter Ions ◽  
Bonding Properties ◽  
Ionic Liquid Crystals

We report on molecular and local orientational order of a series of imidazolium-based ionic liquid crystals exhibiting layered smectic A mesophase. Materials constituting of 1-dodecyl-3-methylimidazolium cation, and different counter-ions, were investigated. We apply two-dimensional 13C-1H dipolar NMR spectroscopy to quantify orientational order of C-H bonds of the organic cation. The experimental data supported the structural model of the interdigitated chains aligned with the smectic layer normal. Molecular order parameter S was found to increase in the anion sequence BF4− < I− < Br− < Cl−. This trend correlates well with ionic radius, negative charge delocalization, and hydrogen-bonding properties of the anions.

scholarly journals Low temperature glass/crystal transition in ionic liquids determined by H-bond vs. coulombic strength

2020 ◽  
Vol 22 (36) ◽  
pp. 20524-20530
Author(s):  
Carlos López-Bueno ◽  
Marius R. Bittermann ◽  
Bruno Dacuña-Mariño ◽  
Antonio Luis Llamas-Saiz ◽  
María del Carmen Giménez-López ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Solar Cells ◽  
Liquid Crystals ◽  
Low Temperature ◽  
Ionic Conductors ◽  
Potential Applications ◽  
Crystal Transition ◽  
Ionic Liquid Crystals ◽  
Glass Crystal

Self-assembled ionic liquid crystals are anisotropic ionic conductors, with potential applications in areas as important as solar cells, battery electrolytes and catalysis. We show that the type of crystal formed depend on the strength of H-bonds.

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