Dynamic simulation of sediment films of Yukawa-stabilized particles

The fast lubrication dynamics method is applied to simulate the motion and deposition of charge-stabilized 100-nm-diam particles into sediment films from aqueous dispersions. Colloidal interactions are incorporated with a Yukawa potential and the effects of the screened-Coulomb potential strength and Péclet number (which controls the sedimentation driving force) on particle orientation are quantified with a sixfold bond order parameter. The effect of sediment growth rate on the order parameter is determined and related to a competition between the electrostatic interaction strength and sedimentation driving force. Increasing the electrostatic interaction strength and decreasing the Péclet number lead to lower sediment growth rates and consequently greater sixfold bond order. Our work demonstrates the feasibility of including lubrication interactions in dynamic simulations of sediment films and suggests that these interactions play a central role in the kinetics of film microstructure development and consequently in the degree of order within the film.