MOLECULAR-DYNAMIC MODELING OF THE AGGREGATION OF COLLOIDAL PARTICLES

The time evolution of a dispersion at T = 273 K with a volume fraction of colloidal particles equal to 0.1 is studied by the method of molec ular dynamics in an NVT ensemble for N = 12 particles. The particles a re studied inside a spherical cell of volume V with walls that elastic ally reflect the particles. The pairwise interaction of the particles is determined by the forces of molecular attraction and short-range re pulsion, resulting in a potential-well depth of 5.5 kT (for a Hamaker constant A = 10(-13) erg) and 2.75 kT (for A = 5.10(-14) erg). The kin etics of evolution of the system is followed from the state in which t he particles are distributed over the volume of the cell to the state in which the system is in dynamic equilibrium - when the particles for m a single aggregate. The kinetics of coagulation follows Smolukhovski i's theory. A decrease in the depth of the potential well is accompani ed by an increase in the length of the coagulation period and the appe arance of monomers in the vapor phase. These monomers randomly separat e from and rejoin the aggregate.