E. Donath, A. Krabi, M. Nirschl,
V. M. Shilov, M. I. Zharkikh, B. Vincent
The Stokes friction coefficient has been calculated for the case of polymer depletion near a spherical particle surface, to provide a theoretical background for the interpretation of dynamic light scattering data. In a quasi-flat Newtonian approximation an analytical solution for arbitrary viscosity profiles was obtained. Numerical integration of the Navier-Stokes equation confirmed the large range of applicability of the approximate analytical solution. Explicit equations for an exponential and a step viscosity profile are given.To compare experiment and theory, dynamic tight scattering data of liposomes with different radii in 110 kDa dextran are presented. For the first time evidence of a depletion layer relaxation effect has been obtained. This relaxation caused an effective reduction of the depletion layer thickness for small particles. A linear correction for the relaxation effect is suggested.
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Received 2 May 1999
Published : J. Chem Soc. Faraday trans, 1997, vol. 93, № 1, p. 115 – 119.
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