title: Percolation of colloids with distinct interaction sites.
abstract: We generalize the Flory-Stockmayer theory of percolation to a model of associating (patchy) colloids, which consists of hard spherical particles, having on their surfaces f short-ranged-attractive sites of m different types. These sites can form bonds between particles and thus promote self-assembly. It is shown that the percolation threshold is given in terms of the eigenvalues of a m X m matrix, which describes the recursive relations for the number of bonded particles on the ith level of a cluster with no loops; percolation occurs when the largest of these eigenvalues equals unity. Expressions for the probability that a particle is not bonded to the giant cluster, for the average cluster size and the average size of a cluster to which a randomly chosen particle belongs, are also derived. Explicit results for these quantities are computed for the case f=3 and m=2 . We show how these structural properties are related to the thermodynamics of the associating system by regarding bond formation as a (equilibrium) chemical reaction. This solution of the percolation problem, combined with Wertheim's thermodynamic first-order perturbation theory, allows the investigation of the interplay between phase behavior and cluster formation for general models of patchy colloids.
authors.affiliation: Instituto Superior de Engenharia de Lisboa, Rua Conselheiro Emídio Navarro, Lisbon, Portugal.
authors.forename: J M
authors.initials: JM
authors.lastname: Tavares
authors.forename: P I C
authors.initials: PI
authors.lastname: Teixeira
authors.forename: M M
authors.initials: MM
authors.lastname: Telo da Gama