The viscosity of glycerol-water mixtures including the supercooled region.

J. TREJO GONZALEZ; M. P. LONGINOTTI; H. R. CORTI

JOURNAL OF CHEMICAL AND ENGINEERING DATA

AMER CHEMICAL SOC

Lugar: Washington; Año: 2011 vol. 56 p. 1397 - 1406

0021-9568

We critically analyze all the viscosity data available for water, glycerol and its mixtures over awide range of temperatures, which include the supercooled region. The viscosity of the purecomponents can be described within the experimental error using different empirical equations,although the Avramov-Milchev equation, having only two adjustable parameters describedquite well the temperature dependence of their viscosities. The analysis of the glycerol-watermixtures reveals that, in contrast to that previously found in other aqueous solutions of sucroseand trehalose, the temperature and composition dependence of the viscosity cannot bedescribed by a scaled Arrhenius equation. The same model was used to describe the viscosityof the mixtures over all the range of temperature and compositions where experimental data areavailable, and to extrapolate the mixture viscosities at temperatures close to the glass transition.We calculated the viscosities of the glycerol-water mixtures, all over the range ofcompositions, in the range of temperature form 0o down to –35 oC. The agreement withexperimental data in the stable liquid region is very good, what makes our predictions in thesupercooled region fairly reliable. Finally, we determined the excess viscosity of the mixturesand showed that at low temperatures the glycerol-water mixtures seems to become regularsolutions.