The free-radical cotelomerization of 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) with 1,1,2,2-tetrahydroperfluorodecyl acrylate (PFDA) in the presence of 2-mercaptoethanol was performed at 80 degrees C in acetonitrile. Hydroxy endgroups of the cotelomers were reacted with 2-isocyanatoethyl methacrylate to give macromonomers. The P(TMSPMA-stat-PFDA) cotelomers, containing fluoro and silane groups, were then grafted onto silica nanoparticles. Optimal grafting conditions were found with TMSPMA monomer alone in toluene at 110 degrees C. The structure of the modified silica was analyzed by FTIR and Si-29 solid-state NMR. The amount of grafted TMSPMA or P(TMSPMA-stat-PFDA) was calculated by thermogravimetric and elemental analyzes. The grafting yield increased with the copolymer/silica weight ratio until a maximum value of 2.26 mu mol/m(2). (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4617-4628, 2009