Computer simulation of particle gel formation

Abstract

A model of particle gelation is introduced incorporating flexible irreversible bond formation and attractive or repulsive particle–particle interactions. Starting from a pseudo-random distribution of particles in a two-dimensional periodic cell, aggregation is simulated by the technique of Brownian dynamics until a network structure is produced with all, or nearly all, the particles in a single self-connected aggregate. Numerical data relating to the network and pore structures of the simulated gels are presented as a function of the particle reactivity and the strength of the interparticle interactions. It is shown that a repulsive interparticle interaction is necessary in order to produce a particle gel with a small average pore size. Simulated network structures containing particles with attractive interparticle forces can have fine or coarse pore distributions depending on the relative rates of cross-linking and phase separation. The model reproduces many of the experimental structural features found in particle gels containing proteins.