Interfacial Strength Improvement of 30 wt% GF / PET ‐ A2024 by the Combination of Multiscale Mechanical Interlocking and π–π Stacking/Hydrogen Bonds

ABSTRACT The interfacial strength of 30 wt% GF/PET‐A2024 joint was enhanced via surface treatment of ultrasonic‐assisted N ₂ H ₄ solution corrosion and phenolic resin interlayer. N ₂ H ₄ corrosion forms a multiscale “crater + nanopore” morphology on the A2024 surface, enabling multiscale mechanical interlocking. PR forms AO bonds with A2024 and π–π stacking/hydrogen bonds with PET, creating a chemical “bridge” between the joining surface of PET and A2024. This synergistic effect increases the interface strength from 3.45 MPa (sandpapered) to 29.15 MPa. Density functional theory confirms the stability of π–π stacking interactions, and molecular dynamics simulation reveals that the morphology on the A2024 surface enhances the mechanical interlocking of the joint. This work provides theoretical guidance for improving resin/aluminum interfaces and highlights the potential of micro‐nano morphology and supramolecular interactions in strengthening interface adhesion.