Fracture Behavior of Alumina/Epoxy Resin Interface and Effect of Water Molecules by Using Molecular Dynamics Using Reaction Force Field (ReaxFF)

Adhesion bonding of metals and polymers is attracting attention as an innovative bonding technology to realize high functionality and weight reduction of various mechanical parts and structural materials. This technology has been significantly demanded with the rapid development of multi-materials in recent years. However, it has been reported that natural oxide film and hydroxide film are formed on the metal surface, resulting in the change in adhesion, especially degradation of adhesion is sometimes accelerated by water molecules at the interface. The mechanism of adhesion degradation is still unclear. In this study, the interface between metal and resin was modeled using the molecular dynamics (MD) simulation to investigate how the moisture (water molecules) on the interfacial surface affects the adhesion. This study varied the amount of water molecules at the interface and investigated how water molecules affect the adhesive strength subjected to uni-axial tensile loading. In addition, the potential energy around the interface was calculated, and the adhesion mechanism with respected to water molecules was carefully discussed.