Short-time rheology and diffusion in suspensions of Yukawa-type colloidal particles

Heinen, M.; Banchio, A.J.; Nägele, G.

doi:10.1063/1.3646962

Journal Article

PreJuSER-16797

Short-time rheology and diffusion in suspensions of Yukawa-type colloidal particles

Heinen, M.FZJ* ; Banchio, A. J. ; Nägele, G.FZJ*

2011
American Institute of Physics Melville, NY

The journal of chemical physics 135, 154504 (2011) [10.1063/1.3646962]

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Please use a persistent id in citations: http://hdl.handle.net/2128/4637 doi:10.1063/1.3646962

Abstract: A comprehensive study is presented on the short-time dynamics in suspensions of charged colloidal spheres. The explored parameter space covers the major part of the fluid-state regime, with colloid concentrations extending up to the freezing transition. The particles are assumed to interact directly by a hard-core plus screened Coulomb potential, and indirectly by solvent-mediated hydrodynamic interactions. By comparison with accurate accelerated Stokesian Dynamics (ASD) simulations of the hydrodynamic function H(q), and the high-frequency viscosity η(∞), we investigate the accuracy of two fast and easy-to-implement analytical schemes. The first scheme, referred to as the pairwise additive (PA) scheme, uses exact two-body hydrodynamic mobility tensors. It is in good agreement with the ASD simulations of H(q) and η(∞), for smaller volume fractions up to about 10% and 20%, respectively. The second scheme is a hybrid method combining the virtues of the δγ scheme by Beenakker and Mazur with those of the PA scheme. It leads to predictions in good agreement with the simulation data, for all considered concentrations, combining thus precision with computational efficiency. The hybrid method is used to test the accuracy of a generalized Stokes-Einstein (GSE) relation proposed by Kholodenko and Douglas, showing its severe violation in low salinity systems. For hard spheres, however, this GSE relation applies decently well.

Keyword(s): Colloids: chemistry (MeSH) ; Computer Simulation (MeSH) ; Diffusion (MeSH) ; Models, Chemical (MeSH) ; Particle Size (MeSH) ; Rheology (MeSH) ; Suspensions (MeSH) ; Time Factors (MeSH) ; Viscosity (MeSH) ; Colloids ; Suspensions ; J ; colloids (auto) ; diffusion (auto) ; electric potential (auto) ; fluids (auto) ; freezing (auto) ; hydrodynamics (auto) ; rheology (auto) ; suspensions (auto) ; viscosity (auto)

Classification:

Physics, Atomic, Molecular & Chemical

Note: M.H. acknowledges support by the International Helmholtz Research School of Biophysics and Soft Matter (IHRS BioSoft). A.J.B. acknowledges financial support from SeCyT-UNC and CONICET. This work was under appropriation of funds from the Deutsche Forschungsgemeinschaft (DFG) (SFB-TR6, project B2).

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