The biofouling propensity and cleaning effectiveness were evaluated for a new generation of polyamide thin-film composite (PA-TFC) membranes that are surface nano-structured (SNS) with terminally anchored hydrophilic polymer chains. The SNS-PA-TFC membranes were formed via surface graft polymerization onto the surface of polyamide base membranes previously activated via surface treatment with atmospheric pressure plasma. Poly(methacrylic acid) (PMMA) and polyacrylamide (PAAm) SNS-PA-TFC membranes were synthesized and evaluated with respect to their biofouling resistance using secondary wastewater from a municipal wastewater treatment (MWT) plant. Biofouling resistance and cleaning effectiveness were quantified via flux decline measurements in addition to imaging of the biofouled membranes before and after DI water and chemical (Na-2 center dot EDTA) cleaning. Increased biofouling resistance was highest for the PMAA-SNS-PA-TFC membrane being a factor of 4.2 greater than for the commercial membrane of about the same salt rejection used in the MWT plant. Moreover, permeability recovery for the PMAA-SNS-PA-TFC membrane was higher by factors of up to similar to 1.2 relative to the reference commercial membrane upon cleaning with DI water and more aggressive chemical cleaning at high pressure. The present evaluation of the SNS-PA-TFC membranes suggests that biofouling resistance and cleaning effectiveness of RO membranes can be enhanced via hydrophilic brush layers. (C) 2013 Elsevier B.V. All rights reserved.