Interfacial electrodynamics of interacting colloidal particles. Geometrical aspects

Abstract

The paper treats the effects of geometrical factors on the various double layer relaxation processes which may occur during interaction between colloidal particles. It is explained how the existing theory for interaction between flat plates can be extended to more involved geometries by taking into account the effective region of double layer overlap. Furthermore, the relation between particle interaction dynamics and the kinetics of electrodes of the same material is discussed in terms of the difference in geometry. Finally it is examined how the dielectric relaxation of a colloidal dispersion can be related to the electrodynamics of interaction between individual particles. Some conclusions are drawn on the occurrence of diffuse layer relaxation and interfacial transfer of exchangeable ions in the colloidal system.

Kinetics of deposition of colloidal particles in porous media

“…(c) Dynamics of Interaction. Studies of interfacial electrodynamics (52,53) point out that it is possible, by considering the dynamics of interacting double layers, to provide some basis for the apparent insensitivity of colloidal stability to particle size. It was found that the extent of lateral adjustment of charge during interaction is dominated by hydrodynamic drag.…”

“…The effect of surface roughness on attachment efficiencies as discussed above is for static electrical double layer interaction theories. Surface roughness may also have a notable effect on interfacial dynamics of interaction (52,53). The current understanding of dynamics of interaction is very poor and its effect on colloidal stability cannot be assessed quantitatively.…”

Interactions between single-walled carbon nanotubes and lysozyme

“…Electrophoretic mobility is a powerful tool to investigate colloid dispersions and may give significant information on the charge distribution around polymers, latexes, powders, silica or titania nano-particles, nanotubes [20,21], proteins, DNA and many other biologically relevant molecules. Very presumably, the interactions between biopolymers and nanotubes imply significant changes at interfaces, with subsequent modifications in the electrical double layer surrounding colloid particles in water [22]. Dielectric studies can give relevant information on this regard, since they allow determining polarization effects and changes in charge distribution around interfaces [23].…”

Lysozyme binding onto cat-anionic vesicles

“…The double layer thickness and the residual surface charge density on the lipo-plexes are affected from protein-vesicle interactions, with subsequent effects on their surface charge. Dielectric spectroscopy detects the charge polarization at interfaces, and, more generally, assesses modifications in the electrical double layer around colloid particles [24]. It is also used to investigate surfactant binding to DNA [25], to detect the conformation of proteins in mixed solvents [26], and to measure the diffusion and electrophoretic mobility of vesicles [27].…”