Enhancing interfacial bonding between epoxy and CSH using graphene oxide: An atomistic investigation

Abstract Graphene oxide (GO) is being considered for improving the bonding properties of the epoxy-concrete interface, which is of great significance in enhancing the durability and sustainability of fiber-reinforced polymer (FRP) embedded with concrete structures. Substantial improvement in the bonding performance of epoxy-concrete interface by GO nanomaterial relies heavily on the optimal design of GO-insertion in the interfacial region, and such manipulation requires comprehensive understanding of the interfacial adhesion of the epoxy-concrete interface before and after GO-modification. Herein, the bonding performances of the epoxy-calcium silicate hydrate (CSH) interface with and without the GO-modification are investigated using molecular dynamics simulations. Notably, epoxy adhered to the GO sheet exhibits better resistance to pulling forces than that adhered directly to the CSH surface, which demonstrates bonding improvement after GO-modification. Beyond the hydrogen bonding connections formed between epoxy and oxygen-containing functional groups of GO, the high interactions between epoxy and graphene sheet dominate the excellent performance at the epoxy-GO interface.