Nanoparticles have attracted much attention because of their unusual physical properties, which allow them to be used in many practical applications. The self-assembly of nanocrystals into crystalline arrays can be facilitated by functionalizing the nanocrystals with ligand brushes, allowing for bulk dispersions to be sterically stabilized against aggregation. Studies have been conducted to study the clustering of gold nanoparticle dispersions. To study the self-assembly of gold nanoparticle dispersions based on nanocrystal volume fraction and ligand coverage, we performed Monte Carlo simulations and characterized the ability of the nanoparticle dispersions to self-assemble into crystalline arrays. Experiments have shown that silver nanoparticles can self- assemble into equilibrium superlattices in the presence of free ligands. To better understand the role of adsorbed and free ligands in self-assembly, we extracted the effective pressure between two flat, ligated plates through molecular dynamics simulations. Our results are compared to the theoretical prediction and discrepancies are discussed.