UNORIENTED ADSORPTION OF INTERACTING SPHEROIDAL PARTICLES

Kinetics of localized adsorption of interacting spheroidal particles o n homogeneous interfaces was analyzed theoretically. In contrast to pr evious studies, in our present approach an unoriented (quasi-3D) adsor ption of prolate and oblate spheroids was considered. By applying the random sequential adsorption (RSA) method, numerical Monte Carlo type simulations were performed for colloidal particles interacting via a r epulsive potential stemming from the electrostatic double-layers (expo nentially decaying Yukawa-type potential). The surface blocking parame ter (available surface function) and adsorption kinetics were determin ed for various particle shapes and for a broad range of the Ka paramet er characterizing the range of the interaction potential. It was demon strated that the ''exact'' numerical results can well be described for not too high surface concentrations by the approximate analytical exp ressions derived using the equivalent hard particle concept. On the ot her hand, for surface concentrations close to jamming, adsorption kine tics of interacting particles can well be approximated by the power-la w dependencies analogous to hard particles. The theoretical analysis r evealed that adsorption rate of colloid particles having a spheroidal shape is considerably diminished by the lateral electrostatic interact ions. (C) 1997 Academic Press.