Temperature and Pressure Scaling of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>α</mml:mi></mml:math>Relaxation Process in Fragile Glass Formers: A Dynamic Light Scattering Study

Paluch, Marian; Patkowski, A.; Fischer, Erhard W.

doi:10.1103/physrevlett.85.2140

Cited by 78 publications

(66 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…F and E are pressure independent, whereas the pre-exponential factor is pressure and temperature dependent. Nonetheless, we can observe in the literature that, in the case of the modeling of structural relaxation times using the VFT equation, at moderate pressures (p \ 400 MPa), the Vogel temperature always increases with pressure [45][46][47][48][49][50] whereas the strength parameter D A seems to be pressure independent for some authors [51,52], but it is considered pressure dependent for others [53,54]. Considering these results of the literature, we correlate the viscosities at high pressures using other two modifications of the VFT equation [55,56] given by…”

Section: Viscositymentioning

confidence: 90%

Pressure–Viscosity Coefficients for Polyalkylene Glycol Oils and Other Ester or Ionic Lubricants

et al. 2011

View full text Add to dashboard Cite

We present in this article new viscosity and density data for polypropylene glycol monomethyl ether, which completes a series of articles where we have published dynamic viscosity data of poly(propylene glycol) dimethyl ethers, dipentaerythritol esters, and pentaerythritol esters. New dynamic viscosity measurements up to 60 MPa at five temperatures in the range of 303.15-373.15 K, and density values at temperatures ranging from 298.15 to 398.15 K up to 60 MPa are reported in addition to other physical properties that affect the behavior of the fluids in elastohydrodynamic lubrication regime, such as the viscosity index value, VI, the universal pressure-viscosity coefficient, a film , and the temperature-viscosity coefficient, b. The experimental measurements were performed using a rotational automated viscometer Anton Paar Stabinger SVM3000, a rolling-ball viscometer Ruska 1602-830 for high pressures, and an automated Anton Paar DMA HPM vibrating-tube densimeter. Together with these data, we also present a comparison of the film-generating capability for the fluids above mentioned as well as for other five ionic liquids. We analyze the dependence of the molecular structure on the lubrication properties of these oils, which can help the lubricant engineers to develop products with enhanced performance.

show abstract

Section: Viscositymentioning

confidence: 90%

Pressure–Viscosity Coefficients for Polyalkylene Glycol Oils and Other Ester or Ionic Lubricants

et al. 2011

View full text Add to dashboard Cite

show abstract

“…In analogy to that, the pressure dependence of τ s was expressed in terms of the pressure analog of the VFT formula 29 :…”

Section: Discussionmentioning

confidence: 99%

Isotropic Brillouin spectra of liquids having an internal degree of freedom

Patkowski

Gapiński

Meier

et al. 2007

The Journal of Chemical Physics

View full text Add to dashboard Cite

Isotropic Brillouin spectra of the two chemically similar van der Waals glass forming liquids:1,1'-di(4-methoxy-5-methylphenyl)cyclohexane (BMMPC) and 1,1'-bis(p-methoxyphenyl)cyclohexane (BMPC) and ortho-terphenyl (OTP) were studied in a broad temperature and pressure range in order to characterize the effect of intra-molecular relaxations on damping of longitudinal phonons. Such relaxations are present in BMPC, while in BMMPC and OTP they are strongly hindered. We show that in BMPC (with strong internal relaxations) the damping (broadening) of longitudinal phonons (Brillouin peaks) is much stronger than in BMMPC and OTP (with weaker internal relaxations). The contributions of the intramolecular and structural relaxations to the phonon damping can be separated using high pressure, due to their very different pressure dependence. We show that internal relaxations strongly contribute to the damping of longitudinal phonons at all temperatures and should be taken into account in theoretical models describing the Brillouin spectra of supercooled liquids.

show abstract

“…The past few years have actually seen a growing use of hydrostatic pressure in experimental investigations of glass formers (see for instance, [1][2][3][4][5][6][7][8][9]). Such experiments provide a more stringent testing-ground for the numerous models proposed of the structural relaxation time evolution near vitrification.…”

Section: Introductionmentioning

confidence: 99%

Slow dynamics of salol: A pressure- and temperature-dependent light scattering study

et al. 2004

View full text Add to dashboard Cite

We study the slow dynamics of salol by varying both temperature and pressure using photon correlation spectroscopy and pressure-volume-temperature measurements, and compare the behavior of the structural relaxation time with equations derived within the Adam-Gibbs entropy theory and the Cohen-Grest free volume theory. We find that pressure dependent data are crucial to assess the validity of these model equations. Our analysis supports the entropy-based equation, and estimates the configurational entropy of salol at ambient pressure ∼ 70% of the excess entropy.Finally, we investigate the evolution of the shape of the structural relaxation process, and find that a time-temperature-pressure superposition principle holds over the range investigated.

show abstract

Temperature and Pressure Scaling of theαRelaxation Process in Fragile Glass Formers: A Dynamic Light Scattering Study

Cited by 78 publications

References 29 publications

Pressure–Viscosity Coefficients for Polyalkylene Glycol Oils and Other Ester or Ionic Lubricants

Pressure–Viscosity Coefficients for Polyalkylene Glycol Oils and Other Ester or Ionic Lubricants

Isotropic Brillouin spectra of liquids having an internal degree of freedom

Slow dynamics of salol: A pressure- and temperature-dependent light scattering study

Contact Info

Product

Resources

About