Polyether ether ketone (PEEK) is a thermoplastic polymer of high technological relevance and is composed of repeating phenyl ether and benzophenone units. In the present work we will demonstrate the potential of UV irradiation assisted generation of free radicals on the surface benzophenone units to graft a variety of polymer chains on the PEEK surface. Both "grafting-to" and "grafting-from" approaches were explored by using different monomers and polymers. Styrene, butyl acrylate (BA), vinyl phosphonic acid (VPA), acrylic acid (AA), polyacrylic acid (PAA) and monomethoxy terminated oligo(ethylene glycol) methacrylate (MeOEGMA) were successfully utilized for this purpose. The functionalized membranes were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier-transformed Infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), and contact angle (CA) goniometry. PAA and PVPA functionalized PEEK surfaces exhibited pH responsive wettability behavior. PAA functionalized PEEK surfaces were further modified with lysine, which led to the controlled surface wettability over a broader pH range as compared to the simple PAA functionalized surface. The grafting with polyMeOEGMA rendered PEEK surface with nonfouling properties against bacterial growth. Employing this highly economical and simple method, the surface properties of PEEK can be modulated and tuned according to a specific application. (C) 2014 Elsevier B.V. All rights reserved.