Thermal conductivity and viscosity of biphenyl and the terphenyls

Hedley, W.H.; Milnes, M.V.; Yanko, W.H.

doi:10.1021/je60044a041

Cited by 26 publications

(6 citation statements)

References 5 publications

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“…At high strain amplitude, the viscous modulus follows conventional !-scale behaviour, the slope of which indicates the dynamic viscosity (G 00 ¼ Á !). The estimated value ( ¼ 0.011 Pa s at 64 C and 45 mm) is in agreement with the usual tabulated values [19]. Figure 2 details the strain-induced transition from solid-like to viscous behaviour, showing separately its effect on the shear and viscous moduli.…”

Section: Resultssupporting

confidence: 87%

Identification of finite shear-elasticity in the liquid state of molecular and polymeric glass-formers

Noirez¹,

Mendil‐Jakani²,

Baroni³

2011

Philosophical Magazine

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Finite shear elasticity has been identified in the liquid state. The study is expanded to a van der Waal's molecular glass-former, o-terphenyl, and to an ordinary polymer melt, polybutylacrylate, as a function of their molecular weight. These fluids exhibit shear elasticity at the sub-millimetre scale and far above any phase transition. This macroscopic property challenges the conventional terminal relaxation modes (-process or terminal viscoelastic times (reptation)) in terms of individual molecular process. IntroductionTo define three states of matter, such as solid, liquid or glass and the transitions between them, the shear and bulk moduli are certainly the most useful and relevant characteristic features [1]. The shear modulus presents a substantial advantage over bulk modulus because specific instrumentation has been elaborated to routinely measure the dynamic properties of viscoelastic materials (materials displaying dynamic behaviours intermediate between liquid and solid). These apparatuses are dynamic mechanical analysers, rheometers, shear resonators, surface force apparatus, among others. Based on the same principle, these devices measure the stress or motion transmitted by simple contact between the sample and the surface submitted to small mechanical oscillatory solicitations. This mechanical technique is currently the only one able to probe long time scales.The boundary conditions between the surface and the sample play a major role in this measurement since the efficiency of transmission of the motion and, thus, the quality of the measurement are completely dependent on the interaction between the surface and the material. To date, progress in instrumentation sensitivity and techniques has allowed the measurement of shear modulus with a high precision and over six decades of magnitude [2]. These improvements have considerably widened the frequency window and the modulus range, enabling the detection of subtle properties that could not been considered before. Recent developments have shown that it is also

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Section: Resultssupporting

confidence: 87%

Identification of finite shear-elasticity in the liquid state of molecular and polymeric glass-formers

Noirez¹,

Mendil‐Jakani²,

Baroni³

2011

Philosophical Magazine

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“…Figure illustrates the so-called Angell plots for the ILs, except for the ILs not exhibiting glass transitions (Table ). The plots for SiO 2 , and o -terphenyl − are also included in the figure; SiO 2 is one of the strongest compounds, while o -terphenyl is one of the most fragile ones. The ILs in this study exist in the fragile region rather than in the strong region, as is the case of other reported ILs. ,,,, [Pyrr 1(1O2) ][BF 4 ] is stronger than the ILs with other less symmetric anions.…”

Section: Discussionmentioning

confidence: 99%

“…(a) Plots of ln(η) vs T g / T for SiO 2 , (filled black circles), o -terphenyl − (filled black squares), [Pyrr 1(1O2) ][BF 4 ] (red circles), [Pyrr 14 ][OTf] (red squares), [Pyrr 14 ][DCA] (blue circles), [Pyrr 14 ][TCM] (blue squares), [Pyrr 14 ][NTf 2 ] (green circles), [Pyrr 14 ][NF 2 ] (green squares), [Pyrr 14 ][NCyF] (blue diamonds), [Pyrr 1(1O2) ][NTf 2 ] (yellow circles), and [Pyrr 1(1O2) ][NCyF] (yellow diamonds). (b) Magnification scale is given for a clarity of the IL data.…”

Section: Discussionmentioning

confidence: 99%

Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Pyrrolidinium-Based Ionic Liquids: Effects of Anion Species

Kakinuma

Shirota

2019

J. Phys. Chem. B

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We investigated the temperature dependence of the intermolecular vibrational dynamics of pyrrolidinium-based ionic liquids (ILs) with 10 different anion species using femtosecond Raman-induced Kerr effect spectroscopy. The features of the temperature-dependent vibrational spectra vary with the different anions. In the case of the ILs with spherical top anions, such as tetrafluoroborate and hexafluorophosphate, and trifluoromethanesulfonate, the spectral intensity in the low-frequency region below 50 cm–1 increases with rising temperature, while that in the high-frequency region above 50 cm–1 remains almost unchanged. Similar temperature-dependent features were also found in the bis(fluorosulfonyl)amide and bis(perfluoroalkylsulfonyl)amide salts. However, the difference spectra at respective temperature relative to 293 K indicate that the spectra of the bis(fluorosulfonyl)amide and bis(perfluoroalkylsulfonyl)amide salts are more temperature-sensitive in the low-frequency region below 50 cm–1 compared to those of the tetrafluoroborate, hexafluorophosphate, and trifluoromethanesulfonate salts. The spectra of 1-butyl-1-methylpyrrolidinium-based ILs with dicyanamide and tricyanomethide anions show a characteristic temperature dependence; in addition to an increase of the spectral intensity in the low-frequency region below 50 cm–1, a red shift of the spectra in the high-frequency side above 50 cm–1 was observed with increasing temperature. This implies that the librational motions of planar dicyanamide and tricyanomethide anions contribute substantially to the low-frequency spectra. We also compared the temperature-dependent low-frequency spectra of 1-butyl-1-methylpyrrolidinium- and 1-(2-methoxyethyl)-1-methylpyrrolidinium-based ILs with some anions. Although the spectral shapes are slightly different in the range of 70–150 cm–1, which can be attributed to the intramolecular vibrational modes of the cations, the temperature dependence of the spectral shapes is quite similar, indicating that the ether substitution in the cation side groups has little effects on the temperature dependence of the low-frequency spectra. The fragilities of the ILs were also estimated from the temperature-dependent viscosities and the glass-transition temperatures. The fragility parameter seems to be correlated with the temperature dependence of the first moment of the low-frequency spectral bands mainly arising from the intermolecular vibrations of the ILs.

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“…Figure shows the Angell plots for the studied ILs with the exception of [C 4 MIm][OTf] and [C 4 MIm][NCyF], which do not exhibit glass transitions. Plots for the two extreme cases, SiO 2 , and o -terphenyl, − which show strong and fragile features, respectively, are also shown. Figure a reveals that the studied ILs are rather fragile compared to SiO 2 but stronger than o -terphenyl.…”

Section: Discussionmentioning

confidence: 99%

Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Imidazolium-Based Ionic Liquids: Effects of Anion Species and Cation Alkyl Groups

Kakinuma¹,

Ishida

Shirota³

2017

J. Phys. Chem. B

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The temperature dependence of the intermolecular vibrational dynamics in imidazolium-based ionic liquids (ILs) with 10 different anions was studied by femtosecond Raman-induced Kerr effect spectroscopy. For all ILs investigated in this study, the intensity in the low-frequency region below 50 cm increases, and the spectral density in the high-frequency region above 80 cm decreases (and shows a redshift) with increasing temperature. The first phenomenon would be attributed to the activation of the translational vibrational motions, whereas the second one is ascribed to the slowing librational motion of the imidazolium ring with increasing temperature. Calculated spectra of the density of states for the intermolecular vibrations of 1-butyl-3-methylimidazolium hexafluorophosphate, which is one of the experiment samples studied here, obtained by molecular dynamics simulation agreed well with the experimental results and confirmed the spectral assignments. When we compared the difference spectra between spectra measured at various temperatures and the spectrum measured at 293 K, a clear difference was found in the ∼50 cm region of the Kerr spectra of 1-butyl-3-methylimidazolium thiocyanate and 1-butyl-3-methylimidazolium dicyanamide from those of the other ILs. The difference might have originated from the librational motions of the corresponding anions. We also compared the temperature-dependent Kerr spectra of hexafluorophosphate salts of 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, and 1-heptyl-3-methylimidazolium cations. These ILs showed a similar temperature dependence, which was not affected by the alkyl group length. The temperature-dependent viscosities and glass transition temperatures of the ILs were also estimated to determine their fragilities.

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Thermal conductivity and viscosity of biphenyl and the terphenyls

Cited by 26 publications

References 5 publications

Identification of finite shear-elasticity in the liquid state of molecular and polymeric glass-formers

Identification of finite shear-elasticity in the liquid state of molecular and polymeric glass-formers

Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Pyrrolidinium-Based Ionic Liquids: Effects of Anion Species

Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Imidazolium-Based Ionic Liquids: Effects of Anion Species and Cation Alkyl Groups

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