Translational and reorientational dynamics in carboxylic acid-based deep eutectic solvents.
J Chem Phys
; 160(7)2024 Feb 21.
Article
en En
| MEDLINE
| ID: mdl-38380750
ABSTRACT
The glass formation and the dipolar reorientational motions in deep eutectic solvents (DESs) are frequently overlooked, despite their crucial role in defining the room-temperature physiochemical properties. To understand the effects of these dynamics on the ionic conductivity and their relation to the mechanical properties of the DES, we conducted broadband dielectric and rheological spectroscopy over a wide temperature range on three well-established carboxylic acid-based natural DESs. These are the eutectic mixtures of choline chloride with oxalic acid (oxaline), malonic acid (maline), and phenylacetic acid (phenylaceline). In all three DESs, we observe signs of a glass transition in the temperature dependence of their dipolar reorientational and structural dynamics, as well as varying degrees of motional decoupling between the different observed dynamics. Maline and oxaline display a breaking of the Walden rule near the glass-transition temperature, while the relation between the dc conductivity and dipolar relaxation time in both maline and phenylaceline is best described by a power law. The glass-forming properties of the investigated systems not only govern the orientational dipolar motions and rheological properties, which are of interest from a fundamental point of view, but they also affect the dc conductivity, even at room temperature, which is of high technical relevance.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Año:
2024
Tipo del documento:
Article
País de afiliación:
Alemania
Pais de publicación:
Estados Unidos