Adsorption of Colloidal Particles in the Presence of External Fields

Abstract

We present a new class of sequential adsorption models in which the adsorbing particles reach the surface following an inclined direction (shadow models). Capillary electrophoresis, adsorption in the presence of a shear or on an inclined substrate are physical manifestations of these models. Numerical simulations are carried out to show how the new adsorption mechanisms are responsible for the formation of more ordered adsorbed layers and have important implications in the kinetics, in particular modifying the jamming limit.

Oil coating of hydrophobic surfaces from aqueous media: Formation and kinetic study

“…It can be much lower than 1 because of geometrical constraints, shadow effects (due to hydrodynamic interactions between the deposited particles and the flowing ones [15]), and repulsive interactions between particles and also because of microheterogeneity of the surface.…”

Cooperativity in the adsorption of magnetic colloidal particles

“…The model generally accounts for excluded volume (namely, no particle overlap) but not for interactions between the particles. In systems where cooperativity is important and the probability of adsorption depends on the number of particles previously adsorbed onto a surface patch, deviations from the binomial or RSA [5][6][7][8] should arise.…”

“…In systems where cooperativity is negligible the probability of particle adsorption is independent of surface coverage, one would expect to find that the number of particles per adsorbing patch (i.e., occupancy) is given by the binomial distribution (see, for example, [4]), with an average value determined by the binding energy and excluded volume. In this limit, which is also termed Random Sequential Adsorption (RSA), particles bind irreversibly and sequentially to random positions on the surface [5][6][7][8]. The model generally accounts for excluded volume (namely, no particle overlap) but not for interactions between the particles.…”

New Cooperative Effects in Ballistic Deposition of Hard Disks

“…In order to perform detailed simulations of deposition using a reasonable amount of computing time, we will consider the deposition of hard disks instead of hard spheres. At this point, we recall that this is a typical procedure in adsorption-deposition studies: in the two dimensional system it is easier to perform simulations and to obtain analytical results [4,[8][9][10]. The results obtained in the two dimensional system are very useful to guide the analysis of the much more complicated three dimensional system.…”

“…In this case, the saturation coverage has also been obtained analytically ( 1 0:808 65). The success of the BD model in VOLUME 89, NUMBER 27 explaining experimental data [2,4] has motivated the introduction of many improvements in the model in order to account for fine details neglected in the original BD model [9,10]. In the case of BD of hard disks, the effect of hydrodynamic interactions [9] and external fields [10] has been analyzed.…”