Spider silk-inspired rigid-flexible architecture constructed from chitosan, metal-phenolic networks and graphene oxide for synergistically enhanced mechanical and electromagnetic interference shielding properties of composites.

Most existing carbon fiber surface modification methods face challenges such as high cost, environmental pollution, and demanding equipment requirements. Inspired by the hierarchical structure of spider silk in nature, this work proposes a rigid-flexible interfacial engineering strategy to modify carbon fibers through the construction of chitosan, metal-phenolic networks, and graphene oxide coatings. This modification effectively enhances the interfacial adhesion and strengthens the fiber-matrix interface in carbon fiber reinforced polymer composites. The materials used are environmentally friendly and biodegradable, and the modification process is simple and scalable, meeting the requirements of sustainable development. The constructed rigid-flexible architecture leads to significant improvements in interfacial performance, resulting in increases of 47.72%, 46.81%, and 56.61% in interlaminar shear strength, flexural strength, and transverse fiber bundle tensile strength, respectively. In addition, the composites exhibit enhanced electromagnetic interference shielding effectiveness and improved thermal aging stability. The rigid-flexible interfacial architecture increases surface roughness and chemical reactivity of carbon fibers, provides abundant mechanical interlocking sites, and promotes more efficient stress transfer while suppressing crack propagation, thereby contributing to the overall enhancement of composite performance. Overall, this work provides a new strategy for designing high-performance CFRP composites with integrated structural and functional properties.