| Autor: |
Ransom TC; Naval Research Laboratory, Chemistry Division, Code 6100, Washington DC 20375-5342, USA.; Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA., Oliver WF; Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA. |
| Jazyk: |
angličtina |
| Zdroj: |
Physical review letters [Phys Rev Lett] 2017 Jul 14; Vol. 119 (2), pp. 025702. Date of Electronic Publication: 2017 Jul 14. |
| DOI: |
10.1103/PhysRevLett.119.025702 |
| Abstrakt: |
We present a new method that allows direct measurements of the glass transition temperature T_{g} at pressures up to 4.55 GPa in the glass-forming liquid cumene (isopropylbenzene). This new method uses a diamond anvil cell and can measure T_{g} at pressures of 10 GPa or greater. Measuring T_{g} at the glass→liquid transition involves monitoring the disappearance of pressure gradients initially present in the glass, but also takes advantage of the large increase in the volume expansion coefficient α_{p} at T_{g} as the supercooled or superpressed liquid is entered. Accurate T_{g}(P) values in cumene allow us to show that density scaling holds along this isochronous line up to pressures much higher than any previous study, corresponding to a density increase of 29%. Our results for cumene over this huge compression range yield ρ^{γ}/T=C, where C is a constant and where γ=4.77±0.02 for this nonassociated glass-forming system. Finally, high-pressure cumene viscosity data from the literature taken at much lower pressures and at several different temperatures, corresponding to a large dynamic range of nearly 13 orders of magnitude, are shown to superimpose on a plot of η vs ρ^{γ}/T for the same value of γ. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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