scholarly journals Comparison of the Ionic Liquid Crystal Phase of [C12C1im][BF4] and [C12C1im]Cl by Atomistic MD Simulations

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 253 ◽  
Author(s):  
Giacomo Saielli
Keyword(s):  
Ionic Liquid ◽  
Phase 1 ◽  
Md Simulations ◽  
Smectic Phase ◽  
Chloride Salt ◽  
Chloride System ◽  
Large Size ◽  
Lower Charge ◽  
Ionic Liquid Crystals ◽  
Thermal Stability Of

We present fully atomistic molecular dynamics (MD) simulations at 450 K of two ionic liquid crystals in the smectic phase: 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C12C1im][BF4]) and 1-dodecyl-3-methylimidazolium chloride ([C12C1im]Cl). The two systems experimentally exhibit different ranges of thermal stability of the ionic smectic phase: The chloride salt has a more stable LC phase, between 270.3 K and 377.6 K, with a range of SmA of more than 107 K. In contrast, the tetrafluoroborate salt has a smectic phase between 299.6 K and 311.6 K, with a range of mesophase of just 12 K. The MD simulations show that the chloride system is stable in the smectic phase for the 5 ns of simulation, while the tetrafluoroborate salt melts into an isotropic ionic liquid, in qualitative agreement with the experiments. Comparison of the electrostatic and van der Waals energetic contributions enables one to rationalize the observed behavior as being due to the large size of the [BF4] anion: a larger size of the anion means a lower charge density, and therefore a weaker electrostatic interaction in the ionic layer.

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.

The effect of hydration on the stability of Ionic Liquid Crystals: MD simulations of [C14C1im]Cl and [C14C1im]Cl·H2O

2021 ◽  
Author(s):  
Giacomo Saielli
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Md Simulations ◽  
Structural Features ◽  
Thermal Range ◽  
Ionic Liquid Crystals ◽  
The Stability

The thermal range of stability of Ionic Liquid Crystals (ILC) phases of imidazolium ILCs, and the type of mesophase itself, are affected by several molecular structural features, the two prominent...

Microwave-Assisted Synthesis and Mesomorphic Properties of Novel Unsymmetric Imidazolium as Ionic Liquid Crystals

2011 ◽  
Vol 181-182 ◽  
pp. 181-184
Author(s):  
Teng Zhou Yang ◽  
Rui Cheng ◽  
Xu Ying Liu ◽  
Wen Guang Wang ◽  
Jia Ling Pu
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Smectic Phase ◽  
Microwave Assisted Synthesis ◽  
Imidazolium Salts ◽  
Microwave Assisted ◽  
Ionic Liquid Crystals ◽  
Mesomorphic Properties ◽  
Microwave Assisted Method

Two kinds of novel unsymmetric imidazolium salts based ionic liquid crystals (1- [4-(dodecyloxy) phenyl]-3-hexyl/octyl-1H-imidazol-3-ium bromide) were efficiently prepared using a microwave-assisted method. Their mesomorphism has been fully investigated by POM and DSC. The two imidazolium salts displayed typical and good smectic phase textures.

Influence of the ion size on the stability of the smectic phase of ionic liquid crystals

Soft Matter ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 411-420 ◽  
Author(s):  
Wudi Cao ◽  
Beeran Senthilkumar ◽  
Valerio Causin ◽  
Vincent P. Swamy ◽  
Yanting Wang ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Computational Study ◽  
Smectic Phase ◽  
Ionic Liquid Crystals ◽  
The Stability ◽  
Ion Size ◽  
Energetic Interactions

It takes two to tango: an experimental and computational study of ionic liquid crystals reveals the subtle balance between the energetic interactions in the hydrophobic and ionic layers that contribute to the stabilization of the ionic smectic phase.

Phase Transition and Dynamics in Imidazolium-Based Ionic Liquid Crystals through a Metastable Highly Ordered Smectic Phase

2016 ◽  
Vol 120 (23) ◽  
pp. 5291-5300 ◽  
Author(s):  
Yoko Nozaki ◽  
Keito Yamaguchi ◽  
Kenji Tomida ◽  
Natsumi Taniguchi ◽  
Hironori Hara ◽  
...  
Keyword(s):  
Phase Transition ◽  
Ionic Liquid ◽  
Liquid Crystals ◽  
Smectic Phase ◽  
Ionic Liquid Crystals

Cyanobiphenyl versus Alkoxybiphenyl: Which Mesogenic Unit Governs the Mesomorphic Properties of Guanidinium Ionic Liquid Crystals?

2014 ◽  
Vol 67 (7) ◽  
pp. 1088 ◽  
Author(s):  
Johannes Christian Haenle ◽  
Manuel M. Neidhardt ◽  
Stuart Beardsworth ◽  
Jochen Kirres ◽  
Angelika Baro ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Liquid Crystals ◽  
Head Group ◽  
Substitution Pattern ◽  
Smectic A ◽  
Mesophase Formation ◽  
Mesogenic Unit ◽  
Ionic Liquid Crystals ◽  
Mesomorphic Properties ◽  
Thermal Stability Of

A series of phenylguanidinium salts 3·X, which are linked via an alkoxy spacer either to a 4-decyloxy- or 4-cyano-substituted biphenyl mesogen, was prepared and the mesomorphism studied. A decyloxybiphenyl core and a spacer of at least C6 chain length were required for mesophase formation. Replacement of the chloride counterion by other anions like bromide or tetrafluoroborate improved the thermal stability of the mesophase. A comparison of substitution pattern (meta v. para) on the phenyl ring revealed decreased melting and clearing points for the bent cationic head group. All guanidinium ionic liquid crystals 3 displayed only smectic A (SmA) phases. A packing model is assumed where the molecules in a bilayer stack over each other in opposite direction with interdigitated terminal decyloxy groups and spacers.

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