Communications: High-pressure dielectric scaling study of a monohydroxy alcohol

Reiser, Andreas; Kasper, G.; Gainaru, C.; Böhmer, Roland

doi:10.1063/1.3421555

Cited by 40 publications

(33 citation statements)

References 35 publications

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“…This is possibly due to the break-up of the hydrogen bonds and now any reference dipole in the liquid structure is heterogeneous and this in turn leads to a broader distribution of relaxation times. These results appear to be different from those shown by Reiser et al 19 for 2-ethyl-1-hexanol, where they show that the peak corresponding to process II increases, whereas the one for process I decreases in amplitude with increase in pressure. The two loss peaks in 2-ethyl-1-hexanol are shown apart in the frequency domain for pressures of up to at least 1000 MPa (10 kbar) although both processes markedly approach to each other with densification (see Fig.…”

Section: Resultscontrasting

confidence: 56%

“…The rise in the conductivity curves for these three sets of temperatures and pressures do coincide better than those observed by Reiser et al 19 for 2-ethyl-1-hexanol, again seen in Fig. 7.…”

Section: Resultsmentioning

confidence: 46%

“…31 The effects of high pressure on dielectric properties have been investigated by three groups. [18][19][20] A comparison of these results with those found using alternative complementary techniques has led to a controversial interpretation. Fragiadakis et al 18 have given a brief and updated review of this controversy.…”

Section: Introductionmentioning

confidence: 99%

“…24 One of the monohydroxyl alcohols 2-ethyl-1-hexanol has been studied extensively in the literature mainly with a view to resolving as to which of the two processes I or II, is responsible for the structural relaxation. [18][19][20][29][30][31] In particular, dielectric features have been compared with the observations made from calorimetry, 29 mechanical spectroscopy, 29 and recently NMR. 31 The effects of high pressure on dielectric properties have been investigated by three groups.…”

Section: Introductionmentioning

confidence: 99%

“…However recent studies using high hydrostatic pressure [18][19][20] are motivated mainly by two reasons: (i) to resolve a controversy that exists as to whether the predominant process observed in some of the monohydroxy alcohols, which is Debye-like, contribute to the structural relaxation. In this context, the structural relaxation refers to the manner in which the system returns to equilibrium after the field is removed, and whether motions responsible for viscosity and dc conductivity contribute to it, and (ii) to find as to how the effects due to hydrogen-bonding are manifested in the physical properties of biological systems so as to advancing their understanding.…”

Section: Introductionmentioning

confidence: 99%

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Effect of high hydrostatic pressure on the dielectric relaxation in a non-crystallizable monohydroxy alcohol in its supercooled liquid and glassy states

Pawlus

Paluch

Nagaraj

et al. 2011

The Journal of Chemical Physics

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The complex relative permittivity of a non-crystallizable secondary alcohol, 5-methyl-2-hexanol, is measured over a wide range of temperatures and pressures up to 1750 MPa (17.5 kbar). The data at atmospheric pressure (P = 0.101 MPa) are analyzed in terms of three processes, and the results are in complete agreement with that of O. E. Kalinovskaya and J. K. Vij [J. Chem. Phys. 112, 3262 (2000)]. Process I is of the Debye type and process II is of the Davidson-Cole type, whereas process III is identified as the Johari-Goldstein relaxation process. For pressures of ∼500 MPa and higher, processes I and II are seen to merge into each other to form a single dominant process which unambiguously cannot be resolved into more than one process. The dielectric relaxation strength of process I decreases slightly initially with pressure and when the two processes have merged at elevated pressures, the total relaxation strength increases with increase in pressure. Process III is better resolvable at higher pressures especially above T g in the supercooled liquid state for the reason that the separation in the time scales between the dominant and the JG relaxation process increases at elevated pressures. Surprisingly we find a change in the slope in the plot of log τ JG vs. 1/T for P = 1750 MPa. The results for the relaxation time of alcohols are compared with the Kirkwood correlation factor, g, and it is found that higher is the g, lower is the relaxation time for process I, and it is more of the Debye type. On a reduction in g brought about by an increase in pressure at lower temperatures, the dominant process becomes non-Debye though extensive hydrogen bonding is still present. The dielectric strength of the merged processes increases with increase in pressure. The values of the steepness index, m = |d log τ /d(T g /T)| T = Tg for processes I and II are different for P = 0.1 MPa. However the value of m, for the composite process, which is a merger of processes I and II, for P = 1750 MPa is almost the same for process II at P = 0.1 MPa. From the results of the activation volume, activation enthalpy, and a comparison of the relaxation times with the g factor, we conclude that both processes I and II are significantly affected by hydrogen bonding and both contribute to the structural relaxation.

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Section: Resultscontrasting

confidence: 56%

Section: Resultsmentioning

confidence: 46%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of high hydrostatic pressure on the dielectric relaxation in a non-crystallizable monohydroxy alcohol in its supercooled liquid and glassy states

Pawlus

Paluch

Nagaraj

et al. 2011

The Journal of Chemical Physics

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Oscillatory shear and high-pressure dielectric study of 5-methyl-3-heptanol

et al. 2014

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The monohydroxy alcohol 5-methyl-3-heptanol is studied using rheology at ambient pressure and using dielectric spectroscopy at elevated pressures up to 1.03 GPa. Both experimental techniques reveal that the relaxational behavior of this liquid is intermediate between those that show a large Debye process, such as 2-ethyl-1-hexanol, or a small Debyelike feature, such as 4-methyl-3-heptanol, with which comparisons are made. Various phenomenological approaches assigning a time scale for the rheological signature of supramolecular dynamics in monohydroxy alcohols are discussed.

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