Mechanisms of Surface Evolution in the Modification of Thermoplastic CF / PEEK Composites Using Continuous Laser Irradiation

ABSTRACT Carbon fiber reinforced polyetheretherketone (CF/PEEK) exhibits limited osteogenic capability due to the biological inertia of matrix polyetheretherketone (PEEK), which constrains its application in bone implants. A more cost‐effective continuous laser irradiation surface modification method was proposed to construct a large‐area rough surface on the CF/PEEK by modulating the scanning spacing and laser energy density. At a scanning spacing of 0.6 mm and a laser energy density of 0.56 J/mm ² , the carbonization and graphitization of the irradiated surface were significantly enhanced, resulting in improved hydrophilicity, with the contact angle (CA) changing to 77.9°. Furthermore, the surface roughness ( R _a ) measured 1.96 μm, satisfying the requirements for bone implants. The molecular dynamics simulations, combining coarse‐grained (CG) and all‐atom (AA) models, elucidated the atomic‐level laser heat conduction mode and the breaking process of ether and ketone bonds in the PEEK, as well as the trend of subsequent carbocyclic reconstruction and graphitization. These findings confirmed that laser energy density plays a regulatory role in depolymerization‐remodeling behavior. By optimizing laser processing parameters, the surface properties of CF/PEEK can be controlled, providing an economical and precise new method for developing CF/PEEK bone implants with good osseointegration performance.