Effect of cluster deformations in the DLCA modeling of the sol-gel process

Abstract

The diffusion limited cluster-cluster aggregation (DLCA) model is modified by including cluster deformations during aggregation, with a tuningflexibility parameterF. A three-dimensional computer simulation is presented, which starts from a collection off-functional monomers randomly distributed in a cubic box with a volumic fractionc (concentration) and which uses the highly efficientbond fluctuation algorithm to describe the cluster deformations. It is shown that, forF≠0, there exists a well defined threshold value of the volumic fraction below which the realization of all intra-aggregate bonding possibilities prevents the formation of a gelling network. Forc>c_g, atrue sol-gel transition occurs at a characteristic timet_g, after which an infinite cluster (which is self connected via the boundary conditions) appears. In contrast to DLCA,t_g does not increase as the box size increases. The transition atc_g is characterized by a divergence of the final clusters size forc<c_g and a divergence of the gel time forc>c_g. Several other numerical results are reported.