Molecular dynamics simulation of characteristics of polymer matrices in nanocomposites

Interfaces are considered to play a predominant role in polymer nanocomposites. Many studies have been made in terms of macroscopic characteristic parameters such as permittivity, breakdown voltage and partial discharge resistance. However, few studies have been made to clarify the mesoscopic structures of interfaces between inorganic nano-fillers and surrounding polymer matrices. We conducted a coarse-grained molecular dynamics simulation to investigate the segment motion of polymers near nano-fillers. Parameters of the Lennard Jones potential between surfaces of nano-fillers and polymer segments were changed to simulate "wetting" and "de-wetting" conditions. Two regions of interfaces were clearly recognized as the outcome of the simulation, namely, one where polymer chains are totally bonded to the inorganic substrate, and one where their segmental motion is partially restricted.