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Critical exponent for the viscosity of four binary liquids.
- Source :
-
Journal of Chemical Physics . 9/15/1988, Vol. 89 Issue 6, p3694. 11p. - Publication Year :
- 1988
-
Abstract
- We have measured the viscosity of four binary mixtures near their consolute points: (1) methanol+cyclohexane, (2) isobutyric acid+water, (3) nitroethane+3-methylpentane, and (4) 2-butoxyethanol+water. The viscosity data are consistent with the power-law divergence: η∼|T-Tc|-y, with an apparent viscosity exponent in the range 0.0404<y<0.0444. Recent theoretical estimates for y are near 0.032, which is outside the experimental range. The value of y is independent of whether the critical point is an upper or a lower consolute point and of whether the approach toward Tc is at constant pressure or at constant volume. Our torsion oscillator viscometer is unique in its simultaneous low frequency (∼1 Hz) and low shear rate (∼0.1 s-1), allowing its use close to the critical point before encountering non-Newtonian fluid behavior associated with critical slowing down. Nevertheless, we find quantitative evidence for viscoelasticity near the critical point. [ABSTRACT FROM AUTHOR]
- Subjects :
- *VISCOSITY
*LIQUIDS
Subjects
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 89
- Issue :
- 6
- Database :
- Academic Search Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 7649879
- Full Text :
- https://doi.org/10.1063/1.454890