Bio-inspired hierarchical interfacial engineering on carbon fabrics for structural-functional integrated polymer composites

Carbon fabric-reinforced polyimide (CF/PI) composites hold promise for heavy-load tribological applications, but their performance is severely limited by the intrinsic chemical inertness of carbon fabrics. This study proposes a bio-inspired interfacial engineering strategy to achieve structural–functional integration. Specifically, CFs were functionalized with a bovine serum albumin (BSA) buffer layer, while a synthesized phosphorus/silicon hybrid precursor (DOPO-HQ-IPTS) was incorporated into the PI matrix, constructing a robust hierarchical interfacial bridging network. The BSA protein significantly enhances surface wettability, transitioning the resin from anisotropic wicking to uniform isotropic spreading. This biomimetic “core-shell” architecture induces strong mechanical interlocking and chemical cross-linking. Consequently, the optimal composite exhibits a tensile strength of 474.56 MPa (a 61.6% increase), successfully shifting the macroscopic failure mode to cohesive transverse fracture. Furthermore, driven by thermo-mechanical coupling, the hierarchical interface triggers an in-situ tribochemical reaction. It is hypothesized that this thermochemical synergy promotes the plausible formation of a multi-component P-N-Si composite tribofilm and a dense protective char layer. This robust boundary film effectively suppresses three-body abrasive wear, stabilizing the friction coefficient and achieving an 88.16% reduction in wear rate. This work provides an environmentally benign paradigm for designing advanced carbon fabric composites for rigorous environments.