| 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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Andrade, Maria Madalena Dionísio
Universidade Nova de Lisboa
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (31/31 displayed)
- 2024Cryoprotective Polysaccharides with Ordered Gel Structures Induce Ice Growth Anticipation and Survival Enhancement during Cell Cryopreservationcitations
- 2023Study of the mesomorphic properties and conductivity of n-alkyl-2-picolinium ionic liquid crystalscitations
- 2022Polyhydroxyalkanoates from A Mixed Microbial Culturecitations
- 2022Synthesis and characterisation of ionic liquid crystals based on substituted pyridinium cationscitations
- 2021How Molecular Mobility, Physical State, and Drug Distribution Influence the Naproxen Release Profile from Different Mesoporous Silica Matricescitations
- 2021Influence of natural deep eutectic systems in water thermal behavior and their applications in cryopreservationcitations
- 2021Poly(L-lactic acid)/lithium ferrite compositescitations
- 2019A process engineering approach to improve production of P(3HB) by cupriavidus necator from used cooking oilcitations
- 2017Relaxation behavior of polyurethane networks with different composition and crosslinking densitycitations
- 2017Stabilizing Unstable Amorphous Menthol through Inclusion in Mesoporous Silica Hostscitations
- 2016Dissolution enhancement of active pharmaceutical ingredients by therapeutic deep eutectic systemscitations
- 2016Accessing the Physical State and Molecular Mobility of Naproxen Confined to Nanoporous Silica Matrixescitations
- 2015Design of controlled release systems for THEDES - Therapeutic deep eutectic solvents, using supercritical fluid technologycitations
- 2015Electrical properties of lithium ferrite nanoparticles dispersed in a styrene-isoprene-styrene copolymer matrixcitations
- 2015Dipolar motions and ionic conduction in an ibuprofen derived ionic liquidcitations
- 2014Influence of nanoscale confinement on the molecular mobility of ibuprofencitations
- 2014Conversion of fat-containing waste from the margarine manufacturing process into bacterial polyhydroxyalkanoatescitations
- 2014Ion jelly conductive properties using dicyanamide-based ionic liquidscitations
- 2014Self-standing elastomeric composites based on lithium ferrites and their dielectric behaviorcitations
- 2013New method to analyze dielectric relaxation processescitations
- 2012Probing radiation damage by alternated current conductivity as a method to characterize electron hopping conduction in DNA moleculescitations
- 2012Understanding the Ion Jelly Conductivity Mechanismcitations
- 2011Kinetics of free radical polymerization probed by dielectric relaxation spectroscopy under high conductivity conditionscitations
- 2011Molecular dynamics of poly(ATRIF) homopolymer and poly(AN-co-ATRIF) copolymer investigated by dielectric relaxation spectroscopycitations
- 2011Phase Transformations Undergone by Triton X-100 Probed by Differential Scanning Calorimetry and Dielectric Relaxation Spectroscopycitations
- 2007Dielectric and mechanical relaxation processes in methyl acrylate/tri-ethyleneglycol dimethacrylate copolymer networkscitations
- 2007Temperature modulated DSC study of the kinetics of free radical isothermal network polymerizationcitations
- 2007Origin of glassy dynamics in a liquid crystal studied by broadband dielectric and specific heat spectroscopycitations
- 2006Changes in molecular dynamics upon formation of a polymer dispersed liquid crystalcitations
- 2005Rotational Mobility in a Crystal Studied by Dielectric Relaxation Spectroscopy. An Experiment for the Physical Chemistry laboratorycitations
- 2002Dielectric studies of the nematic mixture E7 on a hdroxypropylcellulose substratecitations
Places of action
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article
Origin of glassy dynamics in a liquid crystal studied by broadband dielectric and specific heat spectroscopy
Abstract
A combination of broadband dielectric (10(-2) Hz-10(9) Hz) and specific heat (10(-3) Hz-2x10(3) Hz) spectroscopy is employed to study the molecular dynamics of the glass-forming nematic liquid crystal E7 in a wide temperature range. In the region of the nematic phase the dielectric spectra show two relaxation processes which are expected theoretically: The delta relaxation which corresponds to rotational fluctuations of the molecules around its short axis and the tumbling mode at higher frequencies than the former one. For both processes the temperature dependence of the relaxation rates follows the Vogel-Fulcher-Tammann formula which is characteristic for glassy dynamics. By applying a detailed data analysis, it is shown that close to the glass transition the tumbling mode has a much steeper temperature dependence than the delta process. The former has a Vogel temperature which is by 30 K higher than that of the delta relaxation. Specific heat spectroscopy gives one relaxation process in its temperature and frequency dependence which has to be assigned to the alpha relaxation (dynamic glass transition). The unique and detailed comparison of the temperature dependence of the dielectric and the thermal relaxation rates delivers unambiguously that the dielectric tumbling mode has to be related to the dynamic glass transition.