Modeling the aggregation of partially covered particles: theory and simulation.

A theoretical model for describing the initial stages of the aggregation of partially covered colloidal particles is presented. It is based on the assumption of short-range interactions that may be modeled by a sticking probability on contact. Three types of sticking probabilities are distinguished depending on the collision type, i.e., for bare-bare, bare-covered, and covered-covered collisions. Hence, the model allows an analytical expression for the dimer-formation rate constant k(11), to be deduced as a function of the degree of surface coverage and the three sticking probabilities. The theoretical predictions are contrasted with simulated data. The observed agreement between theory and simulations shows the usefulness of the model for predicting the initial stages of this kind of aggregation processes.