A molecular dynamic simulation method to elucidate the interaction mechanism of nano-SiO 2 in polymer blends

A molecular dynamics simulation is employed to investigate the effects of nano-SiO 2 particles on the properties of polyvinyl alcohol (PVA)/poly(vinyl pyrrolidone) (PVP) blends and demonstrate the interaction mechanism of nano-SiO 2 particles in blend systems. Six blend systems with different concentrations of SiO 2 particles (0–12.8%) and two interfacial interaction models of polymers on the SiO 2 surface were designed and analyzed in terms of density distribution, mechanical properties, fractional free volume, and X-ray diffraction patterns. The incorporation of nano-SiO 2 particles into the PVA/PVP blend systems increased their mechanical properties, densities, and semicrystalline character. Density distribution analysis indicated PVA molecular chains are more easily adsorbed on the SiO 2 surface than PVP molecular chains. Finally, an analysis of binding energies and pair correlation functions of interfacial interaction models revealed the interaction mechanism of nano-SiO 2 particles in PVA/PVP systems. Hydrogen bond interactions between polar functional groups in polymer molecular chains and the hydroxyl groups of the SiO 2 surface are involved in adsorption of the polymers on the SiO 2 surface and explain why nano-SiO 2 particles can significantly influence the properties of PVA/PVP systems.