A feather-inspired interleaf for enhanced interlaminar fracture toughness of carbon fiber reinforced polymer composites

Carbon fiber reinforced polymer (CFRP) composites with lightweight, high-strength and high-modulus properties are in high demand across the fields of aerospace engineering, urban mass transit, new energy and architectural design. However, most CFRP composites suffer from delamination owing to the weak interlayer which plays an important role to transfer perpendicular load to plies. Here, inspired by natural hierarchical structures of feathers, a novel interleaf towards conventional CFRP composites was rationally designed and experimentally proved to be effective for significant enhancement of anti-delamination performance. Interestingly, ZnO nano rods grown on the electrospun nanofibrous mats and carbon fiber bundles formed a kind of cross-scale structure system. It was very similar to the natural hierarchical structures of feathers with rachis, barbs and barbules. Experimental results verified that the introduced hierarchical structures assuredly enhanced the interlayer toughening performance via substantial energy dissipation. When compared with original CFRP composites, the obtained CFRP composites with a feather-inspired interleaf exhibited significantly improved mechanical performance in Mode I and Mode II interlaminar fracture toughness. The proposed bio-inspired design philosophy and feasible fabrication method are anticipated to provide an industry-friendly way to effectively improve the mechanical performance of traditional CFRP composites and promote potential large-scale applications of bioinspired CFRP composites in the broad engineering field.