Poly(N-isopropylacrylamide) thermoresponsive microgel particles with an amine-rich corona were prepared by the copolymerization of N-isopropylacrylamide with N-vinylformamide, NVF. Hydrolysis above the volume phase transition temperature converted the surface formamide moieties to the corresponding amine. The surface amine concentration was enriched by coupling iodine-terminated polyNVF oligomers (DP = 7) to the microgel amines, followed by a second hydrolysis to give the corresponding polyvinylamine. Microgel swelling and electrophoretic mobility values as functions of pH and temperature were consistent with published results for amine-containing microgels. (C) 2004 Elsevier Inc. All rights reserved.