Cluster Formation by Charged Nanoparticles on a Surface in Aqueous Solution

• Published in: Journal of physical chemistry. C 2010-03, Vol.114 (9), p.3754-3762
• Main Authors: Zhang, Dongsheng, González-Mozuelos, Pedro, Olvera de la Cruz, Monica
• Format: Article
• Language: English
• Subjects: C: Nanops and Nanostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp9085238

Clusters of charged nanoparticles in aqueous solutions are analyzed via molecular dynamics simulations. We simulate a two-dimensional system consisting of charged nanoparticles and their corresponding monovalent counterions, with no added salt. The effective pair potentials (EPPs) among these ions are obtained after contracting the water molecules from a full three-dimensional bulk model that explicitly includes the solvent. The dressed interaction site theory (DIST) allows us to adjust the dielectric constant of the solvent to its experimental value and to separate the EPPs among the ions into their short-range and electrostatic (long-range) components. These effective potentials are basically invariant under different ionic concentrations, and the short-range components of those involving at least one nanoparticle are almost independent of the nanoparticle charge. We then use these potentials as the input in our simulations to study cluster formation for different nanoparticle charges at the McMillan−Mayer level of approximation. The structure of the clusters and their net charge (nanoparticles plus absorbed counterions) are also discussed.