| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Branco, Luís C.
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (11/11 displayed)
- 2023Application of Covalent Organic Frameworks (COFs) as Dyes and Additives for Dye-Sensitized Solar Cells (DSSCs)citations
- 2023Study of the mesomorphic properties and conductivity of n-alkyl-2-picolinium ionic liquid crystalscitations
- 2022Ferrocene-Based Porous Organic Polymer (FPOP): Synthesis, Characterization and an Electrochemical Studycitations
- 2022Synthesis and characterisation of ionic liquid crystals based on substituted pyridinium cationscitations
- 2020Application of polyoxometalate-ionic liquids (POM-ILs) in dye-sensitized solar cells (DSSCs)citations
- 2017Membranes with a low loading of Metal–Organic Framework-Supported Ionic Liquids for CO2/N2 separation in CO2 capturecitations
- 2015Characterization of a Novel Intrinsic Luminescent Room-Temperature Ionic Liquid Based on [P-6,P-6,P-6,P-14][ANS]citations
- 2015Electrochromic devices based on disubstituted oxo-bipyridinium ionic liquidscitations
- 2015Dipolar motions and ionic conduction in an ibuprofen derived ionic liquidcitations
- 2010Melting behaviour of ionic salts in the presence of high pressure CO2citations
- 2007Comparison of physicochemical properties of new ionic liquids based on imidazolium, quaternary ammonium, and guanidinium cationscitations
Places of action
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article
Study of the mesomorphic properties and conductivity of n-alkyl-2-picolinium ionic liquid crystals
Abstract
<p>The impact of the alkyl size moiety in the mesomorphic and conductivity properties was evaluated in 2-picolinium ([C<sub>n</sub>-2-Pic]<sup>+</sup>, n = 6 (n-hexyl), 12 (n-dodecyl) and 16 (n-hexadecyl)) organic salts. While the lengthier chains imprint crystalline order, the shortest [C<sub>6</sub>-2-Pic][Br] easily bypasses crystallisation, vitrifying on cooling. Furthermore, both [C<sub>12</sub>-2-Pic][Br] and [C<sub>16</sub>-2-Pic][Br] were found to be ionic liquid crystals (ILCs) due to the emergence of mesophases identified by Polarised Optical Microscopy and confirmed by X-Ray Diffraction, whereas the high mobility of the shortest member impairs the manifestation of LC behaviour. The temperature dependence of conductivity, between −90 to 160 °C, disclosed multiple types of charge transport, ranging from glass transition assisted mechanism in [C<sub>6</sub>-2-Pic][Br] to thermally activated mechanisms for the two ILCs. The Arrhenian activation plots of the direct current (dc) conductivity for both [C<sub>12</sub>-2-Pic][Br] and [C<sub>16</sub>-2-Pic][Br] are sensitive to the materials’ phase transitions and the respective slopes allowed to determine the activation energies. Moreover, ionic diffusion coefficients were estimated in the T-range where dc conductivity is detected, which, for [C<sub>12</sub>-2-Pic][Br] and [C<sub>16</sub>-2-Pic][Br], includes room temperature, contrary to [C<sub>6</sub>-2-Pic][Br] that is highly affected by electrode polarisation starting at cryogenic temperatures. Nyquist and Bode plots were simulated for [C<sub>12</sub>-2-Pic][Br] and [C<sub>16</sub>-2-Pic][Br] at 24 °C by electrical RC circuits, showing a strong dependence of the resistance (R) on the chain length, while the capacitance (C) maintains almost invariant. This supports the hypothesis that charge transport is made through defects, longitudinally to the chains, in the crystalline lattice and between layers, transversally to the chain alignment, in the LC phase. The established correlation between conductivity response and material's physical state should be considered for a rational design of electronic materials tuned by the size of the alkyl tail.</p>