van-der-Waals interaction between two fractal aggregates

The van-der-Waals forces between particles are of fundamental importance for agglomeration processes or their structuring in suspensions. The paper describes a calculation scheme for the corresponding energy potential when the interacting objects are aggregates of colloidal primary particles. This scheme is further employed to examine the impact of aggregate structure on the van-der-Waals interaction. Calculations were therefore conducted for deterministic aggregates with tuneable fractal dimension and for DLCA aggregates of varying size. It appears that the van-der-Waals interaction is governed by the closest pair(s) of primary particles. That results in an impact of the aggregate structure, when the interaction energy is plotted versus the aggregate centre distance. For DLCA aggregates this relationship can be described by a size-independent, but material specific mastercurve.