Shorttime diffusion of chargestabilized colloidal particles: Generic features

M. HEINEN; P. HOLMQVIST; ADOLFO J. BANCHIO; G. NÄGELE

JOURNAL OF APPLIED CRYSTALLOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2010 vol. 43 p. 970 - 980

0021-8898

Analytical theory and Stokesian dynamics simulations are used in conjunction with dynamic light scattering to investigate the role of hydrodynamic interactions in short-time diffusion in suspensions of charge-stabilized colloidal particles. The particles are modeled as solvent-impermeable charged spheres, repelling each other via a screened Coulomb potential. Numerical results for self-diffusion and sedimentation coefficients, as well as hydrodynamic and shorttime diffusion functions, are compared with experimental data for a wide range of volume fractions. The theoretical predictions for the generic behavior of short-time properties obtained from this model are shown to be in full accord with experimental data. In addition, the effects of microion kinetics, nonzero particle porosity and residual attractive forces on the form of the hydrodynamic function are estimated. This serves to rule out possible causes for the strikingly small hydrodynamic function values determined in certain synchrotron radiation experiments.