Cross-Linking Simulation at Metal Oxide-Thermoset Interfaces Using Quantum Chemical and Molecular Dynamics Methods

Abstract Understanding how oxidized metal surfaces catalyze the curing of epoxy resins is essential in improving the reliabilities of epoxy-metal oxide interfaces in multimaterial systems. The catalytic effects of hydroxylated oxidized tin metal (SnO2) surfaces on the cross-linking of epoxy resins were investigated using a hybrid approach that combined quantum chemical calculations with molecular dynamics simulations, wherein the reaction kinetics were modeled using Monte Carlo techniques. Analyzing the reaction pathways and spatial distributions at different hydroxylation levels revealed that fully hydroxylated SnO2 surfaces promoted surface-initiated curing, whereas partially hydroxylated surfaces led to more dispersed reaction propagation. These results highlight the critical roles of the interfacial OH groups in regulating the reaction kinetics, cross-linking density, and polymer network structure. In addition to these mechanistic insights, this study establishes a generalizable methodology for use in probing curing reactions at epoxy-metal oxide interfaces, and it clarifies how metal oxidation states govern interfacial catalysis. Critically, it bridges atomic-scale mechanisms with macroscopic interfacial reliability, addressing the broader question of how the interfacial chemistry dictates the formation and performance of a thermoset network. The conclusions further indicate that surface hydroxylation can be used to regulate the curing efficiency and cross-link distribution, which is critical in rationally designing epoxy formulations and surface treatments.