(360g) Revisiting Nanoparticle Interactions for Effective Nanofluid Modeling and Simulation

The interactions between nanoparticles are studied in this work with atomistic model surfaces and nanoparticles and with three atomistic potential models that were developed based on bulk properties. The results show that the Lennard-Jones potential of pair-wise nature tends to overestimate, while the Sutton-Chen and quantum Sutton-Chen potentials containing explicit many-body effects tend to underestimate. Regardless of the differences between the three potentials, the faceted nanoparticles are found to possess certain shape effects such that the interactions between the nanoparticles depend on the size of the surface facets. When characterized with the atomistically determined results, the Derjaguin approximation is found to be capable of providing interparticle interactions within the atomistically determined ranges and become a more reasonable approach for cases whose underlying interatomic interactions are of pair-wise nature. The Hamaker potential can also provide nanoparticle interactions with the right orders of magnitude. However, both of these classical coarse-grain approaches have the same tendency to underestimate nanoparticle interactions, especially at short distances where they overlook the significance of the discreteness of the interaction centers and excluded volumes. The same cause also makes them unable to exhibit the shape effects for the interactions between small faceted nanoparticles.