A molecular dynamics simulation study of inclusion size effect on polymeric nanocomposites

The elastic behavior of polymeric nanocomposites is investigated with molecular dynamics simulations. Inclusions are modeled as spherical nanoparticles. It is demonstrated with numerically performed tensile tests that Young’s moduli of nanocomposites are strongly affected by the size of the nanoparticle as well as by the interaction strength between polymer chains and the nanoparticle. The Young’s modulus of the nanocomposite is enhanced as the size of the nanoparticle decreases as long as the strength of polymer–nanoparticle interaction is stronger than or equal to that of the polymer–polymer interaction. The analysis of stresses on polymer monomers shows that the composite modulus enhancement by smaller nanoparticles is attributed to the stiffer layer of polymer of higher densities around the nanoparticle.