Surface damage and modification analysis of CF/PEEK under laser irradiation based on experiments and molecular dynamics

Abstract To enhance the surface osseointegration ability of carbon fiber reinforced polyetheretherketone (CF/PEEK), an economical method of continuous laser irradiation was employed to improve its wettability. The effects of different laser energy densities on its surface morphology, chemical structure, and wettability were systematically analyzed. The results showed that at lower laser energy density irradiation, part of the PEEK matrix was removed, forming a rough corrugated surface. At higher laser energy densities, the carbon fibers were exposed and fractured when the damage threshold was reached. Raman spectroscopy and x‐ray photoelectron spectroscopy (XPS) results indicated that laser‐irradiated CF/PEEK surfaces could produce graphene structures. Reax Force Field molecular dynamics (ReaxFF MD) simulation further elucidated the mechanism, where the thermal effect of continuous laser promoted the polymerization of carbon chains in residual PEEK and graphitization of carbon fibers. Notably, at 0.56 J/mm², the irradiated CF/PEEK surface exhibited hydrophilicity without generating new chemical phases, while achieving a surface roughness (R_a = 2.39 μm) consistent with the requirements of bone implants. This study demonstrates that laser irradiation of CF/PEEK surfaces to improve their wettability is feasible, providing a more cost‐effective and efficient method to further improve the processing quality of unidirectional CF/PEEK. Highlights Graphene structure generated on the CF/PEEK surface after laser irradiation. Surface roughness after irradiation meets the requirement of bone implants. The CF/PEEK surfaces after laser irradiation are more hydrophilic. ReaxFF MD is used to investigate material removal and modification mechanisms.