Flocculation and percolation in reversible cluster-cluster aggregation
Polymères Colloïdes Interfaces, UMR 6120 CNRS – Université du Maine, 72085, Le Mans Cedex 9, France
Published online: 28 February 2006
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 (te). te 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 df=2.0 and the size distribution has a power law decay with exponent τ=1.5. At larger values of te transient gels are formed. Close to the percolation threshold the clusters have a fractal dimension df=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.
PACS: 05.10.Ln Monte Carlo methods (see also 02.70.Tt, Uu in mathematical methods in physics; for Monte Carlo methods in plasma simulation, see 52.65.Pp) – / 82.70.Dd Colloids – / 82.70.Gg Gels and sols –
© EDP Sciences/Società Italiana di Fisica/Springer-Verlag, 2006