In this study interfacial polymerization technique was employed by applying trimesoyl chloride (TMC) and piperazine (PIP) as reagents for preparation of polyamide (PA) skin layer on a polyethersulfone (PES) support. Acrylic acid (AA) as a hydrophilic monomer and UV irradiation as a physical procedure were utilized to modify the obtained thin layers. The effect of UV-irradiation and AA concentration on the performance and morphology of modified TFC membranes were investigated. The different concentrations of AA (1%, 5% and 10 wt%) and UV-irradiation times (30, 60 and 120 s) were chosen to modification process. Two sets of modified membranes were prepared: (i) membranes which were modified using UV-irradiation and AA during formation of PA thin film, (ii) membranes which were modified using UV-irradiation and AA after formation of PA thin film. The membranes were characterized by contact angle, SEM, AFM, FTIR, cross-flow filtration set-up and antifouling measurements. First category represented the higher flux and rejection compared to the unmodified membrane. Second category also showed higher rejection. Moreover, the antifouling properties and flux recovery of membranes improved by UV photo-grafting of hydrophilic monomers. Obtained results indicate that first category has significant properties due to the increasing of both flux and rejection. These membranes showed significant anti-fouling. (C) 2012 Elsevier B.V. All rights reserved.