Dynamics in dense suspensions of charge-stabilized colloidal particles.
The dynamic behavior of charge-stabilized colloidal particles in suspension was studied by photon correlation spectroscopy with coherent X-rays (XPCS). The short-time diffusion coefficient, D(Q) , was measured for volume concentrations phi < or = 0.18 and compared to the free particle diffusion constant D(0) and the static structure factor S(Q) . The data show that indirect, hydrodynamic interactions are relevant for the system and hydrodynamic functions were derived. The results are in striking contrast to the predictions of the PA (pairwise-additive approximation) model, but show features typical for a hard-sphere system. The observed mobility is however considerably smaller than the one of a respective hard-sphere system. The hydrodynamic functions can be modelled quantitatively if one allows for an increased effective viscosity relative to the hard-sphere case.
Robert
A
A
European Synchrotron Radiation Facility, B.P. 220, F-38043, Grenoble, France. aymeric@slac.stanford.edu
Wagner
J
J
Härtl
W
W
Autenrieth
T
T
Grübel
G
G
D003102:Colloids / Q000737:chemistry*; D004058:Diffusion; D010316:Particle Size; D017785:Photons; D012212:Rheology; D012996:Solutions / Q000737:chemistry*; D013057:Spectrum Analysis; D055672:Static Electricity; D014783:Viscosity; D014961:X-Ray Diffraction
D003102:Colloids; D012996:Solutions