Adhesion probability of colloidal particles with repulsive soft interaction

Computer simulations of the irreversible adhesion of charged colloidal part icles at a solid/liquid interface are performed to determine whether the di stribution of particles in the vicinity of a preadsorbed (also charged) one follows the Boltzmann law applied to an a priori uniform adhesion probabil ity, as first assumed by Adamczyk et al, (J, Colloid Interface Sci. 140, 12 3 (1990)). If true, this would indicate that the whole information on the d eposition process is contained in the potential energy distribution on the adsorbing surface. In general, diffusion in a field of force and the irreve rsibility of the process induce significant deviations from the Boltzmann-w eighted uniform adhesion density. Nevertheless, it is shown that for partic les characterized by a small gravitational energy this procedure leads to a reasonable first approximation of the distribution of the particles over t he adsorbing surface. This observation thus demonstrates the validity of Ad amczyk's assumption and extends its range of applicability to the case of a weak gravitational field. (C) 1999 Academic Press.