Graphene Oxide Pre‐Installed with a Covalent Adaptable Network Resulted in a “Nacre‐Like” and “Self‐Healable” Multi‐Layered Interface in Carbon Fiber Laminates

This study presents the development of a thermally stable carbon fiber-reinforced epoxy (CFRE) laminate incorporating functional graphene oxide (hGO) and a covalent adaptable network (CAN) to improve interfacial adhesion. Traditional methods, such as nanoflake dispersion or fiber surface modification, have limitations in achieving optimal mechanical reinforcement. The laminate features a multi-layered, "nacre-like" interface stabilized through non-covalent interactions, as supported by density functional theory (DFT) studies. DFT indicates that both polar (electrostatic) and non-polar (π-π) interactions are key to enhancing interfacial strength. A polyetherimide-based sizing agent (BA) with dynamic disulfide bonds is synthesized and applied to carbon fiber (CF) mats to improve bonding. The laminate (BA-CFRE-hGO) is fabricated via vacuum-assisted resin transfer molding, combining BA-coated CF mats with hGO-dispersed epoxy. BA increases CF surface roughness, enhancing mechanical interlocking, while dynamic bonds in BA and hGO strengthen CF-epoxy interactions, creating a "cemented" interface. Optimal BA and hGO concentrations yield a 37% increase in interlaminar shear strength (ILSS), 38% in flexural strength (FS), and a 190% improvement in storage modulus. SEM confirms improved adhesion, and the laminate shows self-healing (57% ILSS recovery), high electromagnetic shielding (∼48 dB at 8.2 GHz), and fast deicing performance, indicating strong potential for aerospace applications.