Toward a better understanding of dielectric responses of van der Waals liquids: The role of chemical structures
- 7 March 2017
- journal article
- research article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 146 (9)
- https://doi.org/10.1063/1.4977736
Abstract
Exhaustive analysis of dielectric relaxation data of van der Waals glass-forming liquids revealed a strong correlation between the width of the frequency dispersion of the α-relaxation and the dielectric strength , originating from the dipole-dipole interaction contribution to the intermolecular potential [M. Paluch et al., Phys. Rev. Lett. 116, 025702 (2016)]. The two van der Waals liquids, 4-vinyl-1,3-dioxolan-2-one (VPC) and 4-ethyl-1,3-dioxolan-2-one (EPC), have chemical structures modified from that of propylene carbonate. All three glass-formers have very similar values of dipole moments, exactly the same dielectric strength, and hence identical frequency dispersion of the α-relaxation in all three glass-formers is expected if the correlation holds. Based on this expectation, we performed dielectric relaxation measurements of the VPC and EPC at ambient and elevated pressures. The results obtained show not only identical α-relaxation frequency dispersion for the three glass-formers but also the excess wing which is the unresolved Johari-Goldstein β-relaxation. On the other hand, the other thermodynamics related parameters of the α-relaxation dynamics, including the glass transition temperature Tg, the fragility index mP, and activation volume , are not uniformly the same for all three glass-formers.
Keywords
Funding Information
- Narodowe Centrum Nauki (DEC-2012/04/A/ST3/00337)
This publication has 30 references indexed in Scilit:
- Many-Body Nature of Relaxation Processes in Glass-Forming SystemsThe Journal of Physical Chemistry Letters, 2012
- Broadband Dielectric Relaxation Study at Ambient and Elevated Pressure of Molecular Dynamics of Pharmaceutical: IndomethacinThe Journal of Physical Chemistry B, 2009
- Erratum: Pressure-induced isothermal glass transition of small organic molecules [Phys. Rev. B72, 094204 (2005)]Physical Review B, 2006
- Does the Interaction Potential Determine Both the Fragility of a Liquid and the Vibrational Properties of Its Glassy State?Physical Review Letters, 2004
- Influence of molecular structure on the dynamics of supercooled van der Waals liquidsPhysical Review E, 2003
- The influence of pressure on dielectric relaxation for phthalate derivatives in the supercooled stateJournal of Physics: Condensed Matter, 1997
- Pressure dependence of the glass transition temperature in molecular liquids and plastic crystalsThe Journal of Physical Chemistry, 1979
- Measurement of the Glass-Transition Temperature of Simple LiquidsThe Journal of Chemical Physics, 1967
- 392. The dipole moments of some cyclic carbonatesJournal of the Chemical Society, 1958
- EDITORIAL SERVICEScience, 1925