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Authors Swiety-Pospiech, A. ; Wojnarowska, Z. ; Hensel-Bielowka, S. ; Pionteck, J. ; Paluch, M.
Title Effect of pressure on decoupling of ionic conductivity from structural relaxation in hydrated protic ionic liquid, lidocaine HCL
Date 30.05.2013
Number 37866
Abstract Broadband dielectric spectroscopy and pressure-temperature-volume methods are employed to investigate the effect of hydrostatic pressure on the conductivity relaxation time (ts), both in the supercooled and glassy states of protic ionic liquid lidocaine hydrochloride monohydrate. Due to the decoupling between the ion conductivity and structural dynamics, the characteristic change in behavior of ts(T) dependence, i.e., from Vogel-Fulcher-Tammann-like to Arrhenius-like behavior, is observed. This crossover is a manifestation of the liquid-glass transition of lidocaine HCl. The similar pattern of behavior was also found for pressure dependent isothermal measurements. However, in this case the transition from one simple volume activated law to another was noticed. Additionally, by analyzing the changes of conductivity relaxation times during isothermal densification of the sample, it was found that compression enhances the decoupling of electrical conductivity from the structural relaxation. Herein, we propose a new parameter, dlogRt/dP, to quantify the pressure sensitivity of the decoupling phenomenon. Finally, the temperature and volume dependence of ts is discussed in terms of thermodynamic scaling concept.
Publisher Journal of Chemical Physics
Wikidata
Citation Journal of Chemical Physics 138 (2013) 204502
DOI https://doi.org/10.1063/1.4807487
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