Bioinspired Laser‐Induced Hierarchical Textures for Enhanced Interfacial Adhesion in <scp>CFRP</scp> Composites

ABSTRACT Carbon fiber reinforced polymer (CFRP), valued for its exceptional strength‐to‐weight ratio and durability, is critical in advanced engineering applications. However, conventional surface treatments often fail to precisely control surface morphology, leading to fiber damage, surface contamination, and uneven roughness—all of which compromise interfacial adhesion and mechanical performance. Here, we present a two‐stage, multi‐mode laser strategy to enhance CFRP joint performance. In the first stage, optimized laser parameters selectively ablate the hydrophobic resin layer and construct bioinspired micro/nanostructures—such as rose petal‐like pillar arrays—on the resin, improving surface hydrophilicity and enabling tunable wetting behavior. Further laser processing induces well‐defined laser‐induced periodic surface structures (LIPSS) on exposed carbon fibers, increasing mechanical interlocking and introducing reactive sites, with the potential for additional functionalities. In the second stage, hierarchical textures inspired by tree frog toe pads and fish scales are engraved onto the fiber surface, further increasing roughness and achieving superhydrophilicity. This dual treatment leads to a substantial increase in tensile shear strength (from 5.9 to 28.5 MPa), while TOF‐SIMS analysis qualitatively confirms enhanced surface oxidation and chemical modification. This approach offers a controllable, environmentally friendly route to robust interfacial adhesion in advanced CFRP composites.