Self-segregating hyperbranched polymer (HBP) additives have been utilized to concentrate silver nanoparticles (AgNPs) at the air interface of polyurethane films. The limited spontaneous surface migration of the AgNPs was enhanced through the addition of appropriately functionalized HBPs. Both amine and thiol terminated additives were employed to allow interaction of the HBP with the nanoparticles. Both types of additives increased surface concentration of silver modestly, though the thiol-terminated HBPs demonstrated nearly a seven-fold enhancement of surface migration. It was also found that wholly-aliphatic HBPs demonstrated only slightly reduced ability to bias AgNP concentration as compared to HBPs functionalized with perfluorinated chains. In addition, films containing 1% total silver concentration were tested for antimicrobial activity using the ASTM-E 2180 protocol. Significant reduction of the microorganisms was observed for all samples, 6-log reduction was achieved for the gram-negative bacteria P. aeruginosa, the gram-positive bacteria S. aureus, and the fungi C. albicans. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013