Equilibrium and kinetic properties of self-assembled Cu nanoparticles: Computer simulations

We present a study of the influence of interparticle interactions on the kinetics of self-assembly and mechanical strength properties of Cu nanoparticulate aggregates. Three types of commonly used inter-particle interaction forces have been considered to account for the attraction between particles, namely electrostatic forces, van der Waals forces and the JKR cohesion model. These models help to account for the forces generated due to surface treatment of particles, a process commonly used in fabricating composite particles. The assembly formed using the electrostatic interaction force model has 50% of the particles positively charged and the remaining particles are negatively charged. All the assemblies considered here have a polydisperse size distribution of particles. To be able to compare the bulk properties predicted between these models, the maximum force required to break the interparticle contacts (pull-off force) is kept identical in all the systems considered here. Three assemblies were generated. The assemblies were allowed to self-assemble based on the three interaction force models as mentioned above. We have studied some of the key properties of self-assembled Cu aggregates obtained by using the above mentioned models. The study shows that, although the pull-off force between particles is identical, variations in the long-range forces between particles significantly affect the structural properties and mechanical strength of the self-assembled nanoaggregates. The approach adopted here forms a basis on which to further probe the bulk behaviour of self-assembled particulates in terms of their single-particle properties.