Study of the relation between diffusion and sedimentation of charged silica sols by dynamic light scattering, ultracentrifugation, and turbidimetry

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Abstract
Measurements of the diffusion coefficient, the sedimentation constant and the turbidity by dynamic light scattering, ultracentrifugation and turbidimetry, respectively, of a charged silica sol as a function of the colloid concentration are reported. The strong repulsive interparticle interactions give rise to a spectacular increase of the inverse osmotic compressibility with concentration. It is found that the generalized Einstein relation between the sedimentation and diffusion coefficients and the osmotic compressibility is satisfied, within the experimental accuracies, at finite concentrations.