Simulation of nanoparticle aggregation using experimental potentials

Vogtt (2017) proposed that the degree of aggregation for nanoparticles is determined by the energy of aggregation. Experimentally determined degrees of aggregation for nanoparticles are used to verify this theory as an input to molecular dynamics simulations using LAMMPS. It is determined that, while thermodynamics governs the equilibrium degree of aggregation, the details of the nanoaggregate structure (such as the number of branches, branch length, and tortuosity of the aggregate minimum path) are determined by a combination of the thermodynamic degree of aggregation and kinetic transport properties. This approach provides a more thorough and useful view of nanoparticle aggregation compared to the Smoluchwski and other kinetic theories. The impact on nanoaggregate structure is compared for free molecular, continuum and the transition transport regimes. This approach results in an understanding of how changes in thermodynamics and transport can lead to the formation of complex hierarchical structures and macroscopic networks from nanoparticles in polymer composites and in thin layers during drying and curing.