A Computational Study of the Size Effect of SiO 2 Spherical Nanoparticles in Water Solvent

Abstract A computational study was carried out at the molecular level through molecular dynamics (MD) simulations to examine how the size of SiO₂ spherical nanoparticles (NPs) influences their surface properties due to molecular interactions. This study comprehensively describes the interaction between SiO₂ spherical NPs and water molecules as a solvent medium. Our goal is to provide valuable insights into the significance of nanoparticle size in understanding their behavior and the resulting changes in the physical properties of materials. Our results indicate that SiO₂ NPs exhibit a strong affinity for water, which increases with the nanoparticle size. This was confirmed by the radial function distribution and hydrogen bond analysis, which revealed a strong interaction between the silanol groups on the SiO₂ NPs and the water molecules. The molecular interactions that control the dynamic behavior of the nanoparticle-water system are hydrogen bond, electrostatic, and dipole-dipole interactions. Furthermore, the results of the elasticity values indicated that SiO₂ NPs only exhibit a high degree of functionality at specific sizes, making them suitable as a size-dependent filler material.