Bioinspired Multi‐Scale Interfacial Architectonics for Synchronous Mechanical‐Environmental Stabilization of PPTA Fibers

The escalating demands for durable poly(p‐phenylene terephthalamide) (PPTA) fibers in harsh service environments necessitate advanced approaches. Inspired by robust interfacial adhesion mechanisms of barnacles, this study prepared a PPTA fiber coated with a nano‐scale polybenzoxazine (PBPZ) coating, and developed a three‐stage etching‐infusion‐curing strategy. The PBPZ coating served both as a mechanical support and as an environmental barrier. Leveraging microvoids in wet‐spun fibers, solvent‐assisted selective etching enabled deep infusion of PBPZ precursors. Subsequent thermal curing during fiber heat treatment formed a resilient interface combining 3D hydrogen bonds and mechanical interlocking. The PBPZ‐coated PPTA fiber exhibited substantial mechanical property enhancements: Young's modulus increased by 25.69% (955.83 ± 39.21 cN/dtex), compression modulus elevated by 53.95% (5.65 ± 0.35 GPa), and interfacial strength (IFSS) achieved an 82.38% enhancement (60.24 ± 3.92 MPa). Significantly, the coated fibers retained 83.67% of Young's modulus after 500 low‐stress cycles. While the PBPZ‐coated fiber achieved synchronized environmental resistance, the PBPZ coating preserved structural and performance integrity through self‐sacrificial protection in strong acids and exhibited excellent UV shielding efficiency, achieving >80% comprehensive performance retention under extreme environmental exposure. This multiscale collaborative reinforcement paradigm established a novel approach for developing multifunctional high‐performance fibers in demanding applications.