Eur. Phys. J. E (2006) 19: 203-211
https://doi.org/10.1140/epje/e2006-00022-7

Regular Articles

Flocculation and percolation in reversible cluster-cluster aggregation

Polymères Colloïdes Interfaces, UMR 6120 CNRS – Université du Maine, 72085, Le Mans Cedex 9, France

^* e-mail: taco.nicolai@univ-lemans.fr
^** e-mail: Jean-Christophe.Gimel@univ-lemans.fr

Received: 1 July 2005
Published online: 28 February 2006

Abstract

Off-lattice dynamic Monte-Carlo simulations were done of reversible cluster-cluster aggregation for spheres that form rigid bonds at contact. The equilibrium properties were found to be determined by the life time of encounters between two particles (t_e). t_e is a function not only of the probability to form or break a bond, but also of the elementary step size of the Brownian motion of the particles. In the flocculation regime the fractal dimension of the clusters is d_f=2.0 and the size distribution has a power law decay with exponent τ=1.5. At larger values of t_e transient gels are formed. Close to the percolation threshold the clusters have a fractal dimension d_f=2.7 and the power law exponent of the size distribution is τ=2.1. The transition between flocculation and percolation occurs at a characteristic weight average aggregation number that decreases with increasing volume fraction.