Rotational and translational self-diffusion in concentrated suspensions of permeable particles

Abade, G.C.; Wajnryb, E.; Ekiel-Jezewska, M.L.; Nägele, G.; Cichocki, B.

doi:10.1063/1.3604813

Journal Article

Rotational and translational self-diffusion in concentrated suspensions of permeable particles

Abade, G. C. ; Cichocki, B. ; Ekiel-Jezewska, M. L. ; Nägele, G.FZJ* ; Wajnryb, E.

2011
American Institute of Physics Melville, NY

The journal of chemical physics 134, 244903 (2011) [10.1063/1.3604813]

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Please use a persistent id in citations: http://hdl.handle.net/2128/4636 doi:10.1063/1.3604813

Abstract: In our recent work on concentrated suspensions of uniformly porous colloidal spheres with excluded volume interactions, a variety of short-time dynamic properties were calculated, except for the rotational self-diffusion coefficient. This missing quantity is included in the present paper. Using a precise hydrodynamic force multipole simulation method, the rotational self-diffusion coefficient is evaluated for concentrated suspensions of permeable particles. Results are presented for particle volume fractions up to 45% and for a wide range of permeability values. From the simulation results and earlier results for the first-order virial coefficient, we find that the rotational self-diffusion coefficient of permeable spheres can be scaled to the corresponding coefficient of impermeable particles of the same size. We also show that a similar scaling applies to the translational self-diffusion coefficient considered earlier. From the scaling relations, accurate analytic approximations for the rotational and translational self-diffusion coefficients in concentrated systems are obtained, useful to the experimental analysis of permeable-particle diffusion. The simulation results for rotational diffusion of permeable particles are used to show that a generalized Stokes-Einstein-Debye relation between rotational self-diffusion coefficient and high-frequency viscosity is not satisfied.

Keyword(s): J ; approximation theory (auto) ; colloids (auto) ; equations of state (auto) ; hydrodynamics (auto) ; permeability (auto) ; self-diffusion (auto) ; suspensions (auto)

Classification:

Physics, Atomic, Molecular & Chemical

Note: M.L.E-J. and E. W. were supported in part by the Polish Ministry of Science and Higher Education Grant No. N501 156538. G.N. thanks M. Heinen for helpful discussions and the Deutsche Forschungsgemeinschaft (SFB-TR6, project B2) for financial support. Numerical simulations were done at NACAD-COPPE/UFRJ in Rio de Janeiro, Brazil, and at the Academic Computer Center in Gdansk, Poland.

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