A Brownian dynamic simulation to verify the effective hard-sphere model criterion for the formation of charged colloidal crystals

Abstract

The mechanism for the formation of colloidal crystals in charge-stabilized colloids is more complicated than that of hard-sphere colloidal crystals. And there is still lack of available criterion for the formation of charged colloidal crystals. The effective hard-sphere model suggests a criterion in which the effective diameter is used as a crucial parameter. In order to test the validity of this criterion, the characteristics of charged colloidal crystals with different effective diameters are investigated using Brownian dynamics simulations in this study. The crystallization behaviors with different geometric particle diameters and repulsive forces are also studied with some fixed effective diameters. In the simulation, the time evolution of crystallization process and the crystal structure during the simulation are characterized by means of the radial distribution functions and bond-order parameters. The results show that the effective hard-sphere model criterion has its reasonableness to some extent. However, the effective diameter cannot be used as the only parameter that influences the formation of charged colloidal crystals. The influence of other parameters should also be taken into account, which indicates that the criterion is one-sided.