Thermodynamic Scaling of the Dynamics of a Strongly Hydrogen-Bonded Glass-Former
| Autor: | Roberto Macovez, Maria Barrio, M. D. Ruiz-Martín, Michela Romanini, Josep Ll. Tamarit, Simone Capaccioli |
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| Přispěvatelé: | Universitat Politècnica de Catalunya. Departament de Física, Universitat Politècnica de Catalunya. GCM - Grup de Caracterització de Materials |
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
thermodynamic scaling Science Thermodynamics 02 engineering and technology Termodinàmica -- Aplicacions 01 natural sciences Article Molecular dynamics 0103 physical sciences Molecule 010306 general physics Supercooling Multidisciplinary Física [Àrees temàtiques de la UPC] Hydrogen bond Relaxation (NMR) 021001 nanoscience & nanotechnology Dynamics Dielectric spectroscopy Intramolecular force Dinàmica Medicine 0210 nano-technology Glass transition |
| Zdroj: | Scientific Reports Scientific Reports, Vol 7, Iss 1, Pp 1-11 (2017) Recercat. Dipósit de la Recerca de Catalunya instname UPCommons. Portal del coneixement obert de la UPC Universitat Politècnica de Catalunya (UPC) |
| Popis: | We probe the temperature- and pressure-dependent specific volume (v) and dipolar dynamics of the amorphous phase (in both the supercooled liquid and glass states) of the ternidazole drug (TDZ). Three molecular dynamic processes are identified by means of dielectric spectroscopy, namely the α relaxation, which vitrifies at the glass transition, a Johari-Goldstein βJG relaxation, and an intramolecular process associated with the relaxation motion of the propanol chain of the TDZ molecule. The lineshapes of dielectric spectra characterized by the same relaxation time (isochronal spectra) are virtually identical, within the studied temperature and pressure ranges, so that the time-temperature-pressure superposition principle holds for TDZ. The α and βJG relaxation times fulfil the density-dependent thermodynamic scaling: master curves result when they are plotted against the thermodynamic quantity Tv γ , with thermodynamic exponent γ approximately equal to 2. These results show that the dynamics of TDZ, a system characterized by strong hydrogen bonding, is characterized by an isomorphism similar to that of van-der-Waals systems. The low value of γ can be rationalized in terms of the relatively weak density-dependence of the dynamics of hydrogen-bonded systems. |
| Databáze: | OpenAIRE |
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