An interfacial grafting radical polymerization method for amphiphilic comb copolymer and shell crosslinked polymer nanocapsules was reported. Macropolyradicals on a water soluble long chain polyamine were generated with hydrogen peroxide in the water phase and subsequent grafting radical polymerization of a vinylic monomer at the water/oil interface proceeded at 65 degrees C. In the presence of a crosslinker, the resulting graft copolymer formed a defined core-shell structure with hydrophilic aqueous core functionalized by the polyamine and a hydrophobic crosslinked polymer shell. The structure of the core-shell material was characterized by NMR, FTIR, DSC, TGA, SEM, TEM, and the mechanism of the graft polymerization is proposed. (c) 2007 Wiley Periodicals, Inc.