▎ 摘　　要

Interfacial aging problem caused by water ingress especially at hygrothermal environment can result in serious performance degradation of fiber reinforced composite. However, detailed mechanism of the interfacial inter-molecular interactions, particularly at the presentence of water, is still a challenging task to be resolved by experiments alone. Herein, novel modeling systems of graphene (GN) and graphene oxide (GO)/epoxy interfaces exposed to liquid water were constructed, respectively, and molecular dynamics simulations were conducted to provide atomic insight into the interfacial structures and dynamics of GN (GO)/epoxy interfaces. The results show that compared with GN/epoxy system, the stronger interfacial van der Waals, electrostatic, and hydrogen bond interactions greatly broaden the interphase region of GO/epoxy interface. However, when the GO/epoxy interface is exposed to water, the sites originally occupied by epoxy molecules will be replaced by water easier. In addition, the investigation of the diffusion behavior of water from interface into epoxy matrix indicates that the diffusion is a stepwise process, which is relatively slow and random. According to our results, no matter for GN/ epoxy or GO/epoxy systems, the ingress of water preferentially happens at the interface, and the GO/epoxy is easier to be influenced by the invading water.