Communication: Thermodynamic scaling of the Debye process in primary alcohols

Pawlus, S.; Paluch, Marian; Grzybowski, Adam

doi:10.1063/1.3540636

Cited by 25 publications

(16 citation statements)

References 27 publications

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“…The three alkanols (methanol, ethanol, and 1-propanol) and two alkoxyethanols deviate from the φ(γ ) behavior given by the rest of compounds analyzed in this work, giving values lower than those to be expected from the γ exponents. Recent results on the scaling of relaxation times of 2-ethyl-1-hexanol performed by Pawlus et al, 31 Reiser et al, 32 and Fragiadakis et al 33 suggest that materials with strong H-bond interactions only conform with the scaling concept over limited ranges of pressure, as eventually a pressure is reached above which the scaling parameter increases with the relaxation time. Thus it is not unexpected that the behavior of alcohols deviates from that of the other compounds considered here.…”

Section: A Viscositymentioning

confidence: 99%

Density scaling of the transport properties of molecular and ionic liquids

López

Pensado

Comuñas

et al. 2011

The Journal of Chemical Physics

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Casalini and Roland [Phys. Rev. E 69, 062501 (2004); J. Non-Cryst. Solids 353, 3936 (2007)] and other authors have found that both the dielectric relaxation times and the viscosity, η, of liquids can be expressed solely as functions of the group (TV (γ)), where T is the temperature, V is the molar volume, and γ a state-independent scaling exponent. Here we report scaling exponents γ, for the viscosities of 46 compounds, including 11 ionic liquids. A generalization of this thermodynamic scaling to other transport properties, namely, the self-diffusion coefficients for ionic and molecular liquids and the electrical conductivity for ionic liquids is examined. Scaling exponents, γ, for the electrical conductivities of six ionic liquids for which viscosity data are available, are found to be quite close to those obtained from viscosities. Using the scaling exponents obtained from viscosities it was possible to correlate molar conductivity over broad ranges of temperature and pressure. However, application of the same procedures to the self-diffusion coefficients, D, of six ionic and 13 molecular liquids leads to superpositioning of poorer quality, as the scaling yields different exponents from those obtained with viscosities and, in the case of the ionic liquids, slightly different values for the anion and the cation. This situation can be improved by using the ratio (D∕T), consistent with the Stokes-Einstein relation, yielding γ values closer to those of viscosity.

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Section: A Viscositymentioning

confidence: 99%

Density scaling of the transport properties of molecular and ionic liquids

López

Pensado

Comuñas

et al. 2011

The Journal of Chemical Physics

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“…g . for water 36 and some monohydroxy alcohols 37, 38 , where the number of hydrogen bonds is lower at higher pressure.…”

Section: Introductionmentioning

confidence: 99%

“…The exponent γ of the thermodynamic scaling can also be estimated as the slope of the logarithmic plot of T g vs v g 48 , where v g is the specific volume at the glass transition, or in general from the slope of ln( T ) vs ln( v ) under isochronal conditions 38 . Figure 6(b) shows the semilogarithmic plot of τ α for each of the four isobaric measurements (Fig.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Scaling of the Dynamics of a Strongly Hydrogen-Bonded Glass-Former

Romanini

Barrio

Macovez

et al. 2017

Sci Rep

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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 β JG 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 β JG 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.

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“…Therefore, a change from slower to faster than exponential behavior in η would be reflected in τ α . Pawlus et al have show that for two monoalcohols this coupling, as well as thermody- namic scaling, only holds under a threshold pressure 37,38 . As shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

Inflection point in the Debye relaxation time of 2-butyl-1-octanol

Thoms

Kołodziej

Wikarek

et al. 2018

The Journal of Chemical Physics

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We report a striking anomaly in the pressure dependent Debye-relaxation time of the branched monohydroxy alcohol 2-butyl-1-octanol. Evidence of a crossover from slower to faster than exponential pressure dependency was obtained at different temperatures via high pressure broadband dielectric spectroscopy. At the same time, viscosity measurements reveal similar behavior in the viscosity respectively the structural relaxation time, indicating a similar origin of the phenomena.

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Communication: Thermodynamic scaling of the Debye process in primary alcohols

Cited by 25 publications

References 27 publications

Density scaling of the transport properties of molecular and ionic liquids

Density scaling of the transport properties of molecular and ionic liquids

Thermodynamic Scaling of the Dynamics of a Strongly Hydrogen-Bonded Glass-Former

Inflection point in the Debye relaxation time of 2-butyl-1-octanol

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