| People | Locations | Statistics |
|---|---|---|
| Naji, M. |
| |
| Motta, Antonella |
| |
| Aletan, Dirar |
| |
| Mohamed, Tarek |
| |
| Ertürk, Emre |
| |
| Taccardi, Nicola |
| |
| Kononenko, Denys |
| |
| Petrov, R. H. | Madrid |
|
| Alshaaer, Mazen | Brussels |
|
| Bih, L. |
| |
| Casati, R. |
| |
| Muller, Hermance |
| |
| Kočí, Jan | Prague |
|
| Šuljagić, Marija |
| |
| Kalteremidou, Kalliopi-Artemi | Brussels |
|
| Azam, Siraj |
| |
| Ospanova, Alyiya |
| |
| Blanpain, Bart |
| |
| Ali, M. A. |
| |
| Popa, V. |
| |
| Rančić, M. |
| |
| Ollier, Nadège |
| |
| Azevedo, Nuno Monteiro |
| |
| Landes, Michael |
| |
| Rignanese, Gian-Marco |
|
Dias, Carlos
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (16/16 displayed)
- 2023Study of the mesomorphic properties and conductivity of n-alkyl-2-picolinium ionic liquid crystalscitations
- 2019Tailoring IGZO composition for enhanced fully solution-based thin film transistorscitations
- 2016Accessing the Physical State and Molecular Mobility of Naproxen Confined to Nanoporous Silica Matrixescitations
- 2013New method to analyze dielectric relaxation processescitations
- 2013Enhancing the Response of Chemocapacitors with Electrospun Nanofiber Filmscitations
- 2012Sintering,Crystallization and Dielectric Behavior of Barium Zinc Borosilicate Glasses - Effect of Barium Oxide substitution for Zinc Oxidecitations
- 2012Understanding the Ion Jelly Conductivity Mechanismcitations
- 2010Charge Carriers Injection/Extraction at the Metal-Polymer Interface and Its Influence in the Capacitive Microelectromechanical Systems-Switches Actuation Voltage
- 2006Development of an ultrasonic motor based on a piezoelectric ceramic sandwiched between two laminate composite plates
- 2006Changes in molecular dynamics upon formation of a polymer dispersed liquid crystalcitations
- 2005Ultrasound role in sol-gel processing of PbTiO3 ceramics
- 2004Capacitance response of polysiloxane films with interdigital electrodes to volatile organic compoundscitations
- 2004Analytical evaluation of the interdigital electrodes capacitance for a multi-layered structurecitations
- 2004Recent Advances in Ceramic-polymer Composite Electretscitations
- 2002Smart materials: the functional properties of ceramic/polymer composites and their relation to sol-gel powder preparationcitations
- 2002Dielectric characterization of PEBA and PDMS for capacitive interdigital vapour sensorscitations
Places of action
| Organizations | Location | People |
|---|
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>