Effects of silica particles on the electrical percolation threshold and thermomechanical properties of epoxy/silver nanocomposites

We experimentally and theoretically demonstrated that the addition of silica particles could improve both the electrical conductivity and the thermomechanical properties of epoxy/silver nanocomposites. As silica particles were added, the electrical percolation threshold concentration of silver nanoparticles decreased and the electrical resistivity of the composite decreased by about 8 orders of magnitude. The coefficient of thermal expansion also decreased with increasing volume fraction of silica particles. Molecular simulations showed that the additional silica particles made the effective intermolecular interactions between silver nanoparticles attractive, thereby enhancing the formation of an electrical percolation network.