Water soluble molecular brush with poly(glycidyl methacrylate) (PGMA) as the main chain and monoallyl terminated poly(ethylene glycol) (PEG) as the densely grafted side chains was efficiently synthesized via grafting-onto approach by copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Then highly efficient post-modification of the ends of the side chains was realized through UV light induced thiol-ene radical addition. Thus polymer brushes with various side chain terminal functional groups including hydroxyl group, carboxyl group, amino group, amino acid, sulfonic group and glucose unit were obtained. (C) 2012 Elsevier Ltd. All rights reserved.