Computer simulation of self-assembly (crystallization) of oppositely charged nanoparticles with various size distributions

Self-assembly of oppositely charged nanoparticles (NPs) of varying diameters into nanoparticle supracrystals was simulated using a combination of Monte Carlo-Molecular Dynamics techniques in an NVT ensemble. The simulated structures were characterized and classified by probabilistic method of structural invariants based on the Wigner sums of spherical harmonics. It is shown that parameters describing the distributions of the sizes of NP: their average value and the dispersion, are crucially important for the spatial distribution of NPs and the local/global structure of the clusters. The role of energy and entropy effects is briefly discussed. Simulation results are in qualitative agreement with experimental trends.