Coupling of hydrodynamic and electric interactions in adsorption of colloidal particles

The role of the coupling between hydrodynamic and electric interactions in adsorption of colloid particles is reviewed. First the general formulation of the problem of fluid motion connected with the macroscopic suspension flow as well as microscopic particle motion is presented together with the general description of the colloid particle adsorption. Then two limiting cases are considered: motion of uncharged particles and electric interactions of stationary particles. The theoretical consideration are supported by illustrative experimental results. Next the electrokinetic effects in particle adsorption process are considered and the theoretical background for the description of these effects is given. The effect of the electroviscous drag on the particle aggregation and adsorption kinetics is discussed. Also the electrokinetic lift force, which is an example of the non-linear electrokinetic effect, is considered and the possible implications on particle adsorption are examined. In the following part of the review the influence of electro-hydrodynamic coupling on the particle transport to the interface is considered. First the 'inverse salt effect' for the initial adsorption flux when the interface is not covered by adsorbed particles is examined. Then, the electro-hydrodynamic scattering effect which occurs when the interface is partially covered by particles is considered and its experimental evidence concerning the adsorption kinetics and the local structure of adsorbate is considered. Also a novel application of the scattering effect to measure interparticle forces the 'colloid particle collider' is presented and some experimental results obtained using this technique are shown. All results reported in this review suggest strong coupling of the hydrodynamic and electric forces and their pronounced influence on colloid particle adsorption. (C) 2000 Elsevier Science B.V. All rights reserved.