A new two-phase route was developed to prepare monodisperse cadmium sulfide (CdS) quantum dots (QDs) with a narrow size distribution. In a two-phase system, chloroform and water were used as separate solvents for palmitoyl chloride functionalized hyperbranched polyamidoamine (HPAMAM-PC) and cadmium acetate/sodium sulfide, respectively. The amphiphilic HPAMAM-PC, with a hydrophilic dendritic core and hydrophobic arms, formed stable unimolecular micelles in chloroform and was used to encapsulate aqueous Cd(2+) ions. After the reaction with S(2-) ions from the aqueous phase, monodisperse and uniform-sized CdS QDs stabilized by HPAMAM-PC unimolecular micelles were obtained. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 991-997, 2011