Polyethylene glycol (PEG) chains with different lengths were covalently bonded to polypropylene membranes by means of RF plasma polymerisation of acrylic acid (pp-Aac) followed by mono-amino PEG attachment in liquid phase. Two reactor configurations were tested for the plasma deposition of ppAAc in order to obtain high retention of carboxylic groups in the deposited thin films. A best configuration was assessed evaluating the membrane surface modifications by means of water droplet adsorption time and contact angles measurements, attenuated total reflection (ATR) spectroscopy and X-ray photoelectron spectroscopy (XPS) analysis. PEG chains were covalently bonded to the best plasma modified membranes and the resulting anti-fouling properties were evaluated.