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Viscosity Measurements of Water at High Temperatures and Pressures Using Dynamic Light Scattering
Ist Teil von
The journal of physical chemistry. B, 2006-09, Vol.110 (37), p.18358-18362
Ort / Verlag
United States: American Chemical Society
Erscheinungsjahr
2006
Link zum Volltext
Quelle
MEDLINE
Beschreibungen/Notizen
The application of dynamic light scattering to measure viscosity of water at high temperatures and pressures is demonstrated. Viscosity was obtained from the translational diffusion coefficient of probe particles dispersed in the medium by the Einstein−Stokes relationship. Measurements were carried out with polystyrene latex, colloidal silica, and colloidal gold. Under a constant pressure of 25 MPa, good agreement was found between the measured and calculated viscosities up to 275 °C with the polystyrene latex, 200 °C with the colloidal silica, and 297 °C with the colloidal gold. It was found that failure of the measurements at high temperatures is ascribed to change in either the dispersion stability or chemical stability of the probe particles. The present results indicate that the technique could also be used for other supercritical fluids having high critical temperature and pressure, such as methanol (T c = 239.4 °C, P c = 8.1 MPa) and ethanol (T c = 243.1 °C, P c = 6.4 MPa).