A Force Field for Describing the Polyvinylpyrrolidone-Mediated Solution-Phase Synthesis of Shape-Selective Ag Nanoparticles

Polyvinylpyrrolidone (PVP), ethylene glycol (EG), and polyethylene oxide (PEO) are key molecules in the solution-phase synthesis of Ag nanostructures. To resolve various aspects of this synthesis, we develop a classical force field to describe the interactions of these molecules with Ag surfaces. We parametrize the force field through force and energy matching to results from first-principles density-functional theory (DFT). Our force field reproduces the DFT binding energies and configurations of these molecules on Ag(100) and Ag(111). Our force field also yields a binding energy for EG on Ag(110) that is in agreement with experiment. Molecular-dynamics simulations based on this force field indicate that the preferential binding affinity of the chains for Ag(100) increases significantly beyond the segment binding energy for PVP decamers, but not for PEO. This agrees with experimental observations that PVP is a more successful structure-directing agent than is PEO.