Towards room temperature ionic liquid crystals: linear versus bent imidazolium phenylpyrimidines

Starkulla, Gundula; Klenk, Simon; Butschies, Martin; Tussetschläger, Stefan; Laschat, Sabine

doi:10.1039/c2jm34595a

Cited by 30 publications

(34 citation statements)

References 45 publications

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“…1,2 The development of ionic liquid (IL)-based electrolytes has been recognized as a viable solution to the safety problems faced by a range of electrochemical devices, including fuel cells, lithium ion batteries, supercapacitors and electrochromic devices. 1,2 The development of ionic liquid (IL)-based electrolytes has been recognized as a viable solution to the safety problems faced by a range of electrochemical devices, including fuel cells, lithium ion batteries, supercapacitors and electrochromic devices.…”

Section: Introductionmentioning

confidence: 99%

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO₂ nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

et al. 2015

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In this article, it is demonstrated that the electrospun poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) nanofibrous mat functionalized with (3-aminopropyl)triethoxysilane is a versatile platform for the fabrication of hybrid nanofibrous mats by covalently attaching various types of inorganic oxide nanoparticles on the nanofiber surface via a sol-gel process. In particular, SiO 2 -on-P(VDF-HFP) nanofibrous mats synthesized using this method is an excellent ionic liquid (IL) host for electrolyte applications. The IL-based electrolytes in the form of free-standing mats are obtained by immersing SiO 2 -on-P(VDF-HFP) mats in two types of liquid electrolytes, namely LiClO 4 /1-butyl-3methylimidazolium tetrafluoroborate and bis(trifluoromethane)sulfonimide lithium salt/1-butyl-1methylpyrrolidinium bis(trifluoromethylsulfonyl)imide. It is found that the surface attached SiO 2 nanoparticles can effectively serve as salt dissociation promoters by interacting with the anions of both ILs and lithium salts through Lewis acid-base interactions. They dramatically enhance the ionic conductivity and lithium transference number of the electrolytes. In addition, better compatibility of the electrolytes with lithium electrodes is also observed in the presence of surface-attached SiO 2 . Using IL-loaded SiO 2 -on-P(VDF-HFP) nanofibrous mats as the electrolytes, electrochromic devices display higher transmittance contrast, while Li/LiCoO 2 batteries show significantly improved C-rate performance and cycling stability. This class of novel non-volatile electrolytes with high ionic conductivity also has the potential to be used in other electrochemical devices.

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Section: Introductionmentioning

confidence: 99%

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO₂ nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

et al. 2015

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“…By using methylsulphonates 6a-d [24] for the Nalkylation reaction of guanidinium chlorides 3a-e · Cl, the corresponding congruent ion pairs with either varying alkyl chain lengths at the counterion (7a-d) or at the cation (7e-h) were obtained (Scheme 2). The reaction of 3d · Cl with sulphonates 8a,b gave the ion pairs 9a,b in 76% and 83% yields, respectively (Scheme 2).…”

Section: Synthesismentioning

confidence: 99%

“…[23] We reported a complementary approach to room temperature mesophases by replacing linear 2-phenylpyrimidines with the corresponding metasubstituted phenylpyrimidines or carboxylic estersubstituted pyrimidines. [24] Previous work on guanidinium sulphonates demonstrated that congruent ion pairs − in which the spherical counterion in classical ILCs is replaced by a mesogenic counterion of similar shape as compared to the mesogenic cation − allow tailoring of the transition temperatures and mesophase range to some extent. [17] We were thus curious whether congruent ion pairs with a bent cation and both spherical and congruent anions would simply affect the transition temperatures or even lead to different mesophase types.…”

Section: Introductionmentioning

confidence: 99%

Ionic liquid crystals derived from guanidinium salts: induction of columnar mesophases by bending of the cationic core

Antill¹,

Neidhardt²,

Kirres³

et al. 2014

Liquid Crystals

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2014) Ionic liquid crystals derived from guanidinium salts: induction of columnar mesophases by bending of the cationic core, Liquid Crystals, 41:7, 976-985, Meta-alkyloxyguanidinium salt-based ionic liquid crystals 3-5, 7 and 9 were synthesised and investigated with respect to the influence of meta-substitution of the cation on the mesomorphic properties. As expected, bending of the mesogenic cation in ion pairs with simple counterions (3-5) decreased melting points irrespective of the anion, but clearing points were influenced by the anion radii. SmA mesophases were formed in all cases. The mesophase formation in guanidinium sulphonates 7 and 9, however, depended not only on meta-substitution but also on the anion, the respective difference between alkyl chain lengths in cation and anion and the number of alkyloxy substituents on the sulphonate, for which a change of mesophase type from smectic to columnar phases was observed. For two derivatives, 7e and 9b, room temperature SmA and Col h mesophases could be obtained that were stable for a temperature range of 91 K and 55 K, respectively. A packing model for both smectic and columnar phases based on powder XRD data was proposed.

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“…Thus, ILCs have attracted considerable attention from both fundamental and applied points of view. [11][12][13][14] Some kinds of ILCs have been reported, and it is claimed that the liquid crystalline behaviour strongly depends on the nature of both the cation and the anion, but also on the length of the alkyl chain of the organic cation. [15] Many other cations and anions have been used to obtain ILCs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterisation of imidazolium-based ionic liquid crystals bearing a cholesteryl mesogenic group

Lan

et al. 2014

Liquid Crystals

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2014) Synthesis and characterisation of imidazolium-based ionic liquid crystals bearing a cholesteryl mesogenic group, Liquid Crystals, 41:12, 1843-1853, A series of cholesteryl-containing imidazolium chlorides and imidazolium tetrachloroaluminates were synthesised, and the chemical structure, liquid crystalline behaviour and ionic conductivity were characterised by several technical methods. Whereas the imidazolium chlorides show chiral smectic A (SmA*) phase on heating and cooling cycles, the imidazolium tetrachloroaluminates display chiral nematic (N*) phase, which is uncommon for ionic liquid crystals (ILCs). The imidazolium chlorides display similar phase transition temperature and entropy, indicating the cholesteryl component influence predominately on the phase transition rather than the different alkyl substituent groups. The imidazolium tetrachloroaluminates show lower melting point temperatures and lower clear point temperature than the imidazolium chlorides. The mesophases exist at rather moderate temperatures. Non-mesomorphic imidazolium tetrachloroaluminate(III) salts with short alkyl substituents have been known for a long time, and the synthesised imidazolium tetrachloroaluminates are the first examples of tetrahalogenoaluminate(III)-containing ILCs. For the imidazolium tetrachloroaluminates, imidazolium cations combine loosely with AlCl 4 − ions because AlCl 4 − ions are large and occupy more space in spite of the hydrogen bond and electrostatic attraction interaction, indicating that the layer structure can be destroyed easily to form N* phase on heating.

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Towards room temperature ionic liquid crystals: linear versus bent imidazolium phenylpyrimidines

Cited by 30 publications

References 45 publications

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO₂ nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO₂ nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

Ionic liquid crystals derived from guanidinium salts: induction of columnar mesophases by bending of the cationic core

Synthesis and characterisation of imidazolium-based ionic liquid crystals bearing a cholesteryl mesogenic group

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Towards room temperature ionic liquid crystals: linear versus bent imidazolium phenylpyrimidines

Cited by 30 publications

References 45 publications

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO2 nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO2 nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

Ionic liquid crystals derived from guanidinium salts: induction of columnar mesophases by bending of the cationic core

Synthesis and characterisation of imidazolium-based ionic liquid crystals bearing a cholesteryl mesogenic group

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Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO₂ nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries

Poly(vinylidene fluoride) nanofibrous mats with covalently attached SiO₂ nanoparticles as an ionic liquid host: enhanced ion transport for electrochromic devices and lithium-ion batteries