ISSN:
1435-1536
Schlagwort(e):
Translational diffusion
;
rotational diffusion
;
hydrodynamic
;
interaction
;
charge-stabilized
;
colloidal suspensions
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
Notizen:
Abstract We study the combined effects of electrostatic and hydrodynamic interactions (HI) on the short-time dynamics of chargestabilized colloidal spheres. For this purpose, we calculate the translational and the rotational selfdiffusion coefficients, D s t and D s r , as function of volume fractionφ for various values of the effective particle chargeZ and various concentrations ns of added 1−1 electrolyte. Our results show that the selfdiffusion coefficients in deionized suspensions are less affected by HI than in suspensions with added electrolyte. For very large ns, we recover the well-known results for hard spheres, i.e. a linearφ-dependence ofD s t andD s r at smallφ. In contrast, for deionized charged suspensions at smallφ, we observe the interesting non-linear scaling propertiesD s t ∝ 1−atφ4/3 andD s r ∝ 1−arφ2. The coefficients at and ar are found to be nearly independent ofZ. The qualitative differences between the dynamics of charged and uncharged particles can be well explained in terms of an effective hard sphere (EHS) model.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF01182441
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