Abstract: A novel method combining sulfonation with alkali treatment for the surface chemical modification of polyetheretherketone(PEEK) was proposed and developed to endow PEEK with significantly enhanced bioactivity. The modified PEEK samples were subjected to the in vitro evaluation on the formation of bone-like apatite. The results showed that the sulfonation treatment improved the hydrophilicity of PEEK by introducing -SO₃H into the surface, and the sulfonation degree and surface morphology of the PEEK samples were influenced by the H₂SO₄ concentration and reactive time. PEEK-S(85%H₂SO₄, 30 min) presented better modification effect than other PEKK-S samples. The NaOH treatment for PEEK-S(85%H₂SO₄, 30 min) introduced Na into the surface and further increased its hydrophilicity, as was also affected by the reactive time. The in vitro bioactivity evaluation via simulated body fluid(SBF) immersion confirmed that the sulfonated PEEK samples treated with NaOH solution, i. e. PEEK-Na had rapid speed to form bone-like apatite on the surface. Only 3 d of soaking in SBF, PEEK-Na(24 h) was fully covered by a layer of bone-like apatite, showing good bioactivity. The current modification method is simple and thus promising for practical applications to improve the bioactivity of PEEK materials.

Key words: Polyetheretherketone(PEEK), Sulfonation, Alkali treatment, Surface composition, Bone-like apatite, Bioactivity