Square root singularity in the viscosity of neutral collodial suspensions at large frequencies
- Delft Univ. of Technology (Netherlands)
- Rockefeller Univ., New York, NY (United States)
The asymptotic frequency, {omega}, dependence of the dynamic viscosity of neutral hard-sphere colloidal suspensions is shown to be of the form {eta}{sub 0}A({phi})({omega}{tau}{sub p}){sup -{1/2}}, where A({phi}) has been determined as a function of the volume fraction for all concentrations in the fluid range, {eta}{sub 0} is the solvent viscosity, and {tau}{sub p} is the Peclet time. For a soft potential it is shown that, to leading order in the steepness, the asymptotic behavior is the same as that for the hard-sphere potential and a condition for the crossover behavior to 1{omega}{tau}{sub p} is given. Our result for the hard-sphere potential generalizes a result of Cichocki and Felderhof obtained at low concentrations and agrees well with the experiments of van der Werff et al. if the usual Stokes-Einstein diffusion coefficient D{degrees} in the Smoluchowski operator is consistently replaced by the short-time self-diffusion coefficient D{sub s}({phi}) for nondilute colloidal suspensions.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-88ER13847
- OSTI ID:
- 569786
- Journal Information:
- Journal of Statistical Physics, Vol. 87, Issue 5-6; Other Information: PBD: Jun 1997
- Country of Publication:
- United States
- Language:
- English
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