Europhys. Lett.
Volume 48, Number 4, November 1999
Page(s) 397 - 402
Section Electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00496-6

Europhys. Lett, 48 (4), pp. 397-402 (1999)

Theory of long-time wave number dependent diffusion coefficients in concentrated neutral colloidal suspensions

R. Verberg 1, I. M. de Schepper 1 and E. G. D. Cohen 2

1 I. R. I. Delft University of Technology - 2629 JB Delft, The Netherlands
2 The Rockefeller University - New York, New York 10021, USA

(received 19 April 1999; accepted in final form 9 September 1999)

PACS. 47.10${\rm +g}$ - Fluid dynamics: General theory.
PACS. 82.70Dd - Colloids.
PACS. 83.10Ff - Continuum mechanics.


We present for the first time a theory for the long-time wave number (k-) dependent collective and self-diffusion coefficients $D^{\rm L}(k,\phi)$ and $D_{\rm S}^{\rm L}(k,\phi)$, respectively, of neutral colloidal suspensions at high volume fractions $\phi$. This theory is based on the Smoluchowski equation with mean-field-like hydrodynamic interactions, cage-diffusion and is free of adjustable parameters. The results provide a molecular interpretation of the experiments by Segrè et al. ( SEGR`E P. N. AND PUSEY P. N., Phys. Rev. Lett., 77 (1996) 771), who recently measured $D^{\rm L}(k,\phi)$ of a concentrated neutral colloidal suspension.


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