High　stability　and　movement　compatibility　under　friction　is　vital　to　guarantee　long-term　use　of　implants　in　the　human　body.　In　this　study,　the　negligible　wear　of　the　poly　(vinylphosphonic　acid)　(PVPA)-modified　Ti6Al4V/polytetrafluoroethylene　(PTFE)　interface　in　phosphate-buffered　saline　(PBS,　PH　=　7.2)　were　confirmed.　The　depth　of　scratches　on　the　PVPA-modified　Ti6Al4V　was　no　more　than　20　nm,　while　there　was　slight　wear　on　the　PTFE　ball,　as　indicated　by　the　radius　of　curvature　being　almost　the　same　as　the　initial　value　after　sliding　for　2　h.　In　addition,　it　should　be　noted　that　the　novel　velocity　and　load-independent　tribological　behaviors　are　exciting.　The　superlubricity　of　the　PVPA-modified　Ti6Al4V　can　be　maintained　over　a　wide　velocity　range,　from　0.3　mm/s　to　48　mm/s,　even　under　a　high　pressure　of　63.49　MPa,　confirming　its　potential　application　in　implants.　The　sufficient　thickness　of　the　firm　PVPA　coatings　with　specific　lubricating　state　and　the　compatibility　of　the　two　tribo-pairs　in　this　tribological　system　primarily　account　for　the　novel　tribological　stability.　This　study　provides　insights　into　the　tribological　mechanisms　of　the　high-stability　polymer　coatings.　(C)　2016　Elsevier　B.V.　All　rights　reserved.