Macromolecules 2009, 42, 1597-1603
1597
One-Pot Synthesis of Hairy Nanoparticles by Emulsion ATRP Ke Min, Haifeng Gao, Jeong Ae Yoon, Wei Wu, Tomasz Kowalewski, and Krzysztof Matyjaszewski* Department of Chemistry, Carnegie Mellon UniVersity, 4400 Fifth AVenue, Pittsburgh, PennsylVania 15213 ReceiVed NoVember 22, 2008; ReVised Manuscript ReceiVed December 31, 2008
ABSTRACT: An efficient one-pot synthesis of hairy nanoparticles was developed by applying ATRP to a twostep sequential emulsion copolymerization. The first step was a microemulsion ATRP of methyl methacrylate (MMA) monomer and ethylene glycol dimethacrylate (EGDMA) cross-linker, leading to uniform nanogels with hydrodynamic diameter Dh ) 31 nm, determined by dynamic light scattering measurement. Addition of a second monomer, n-butyl acrylate (nBA), to the microemulsion successfully converted the system into an emulsion polymerization, and linear PnBA arms grew from the retained initiating sites in the nanogels, forming hairy nanoparticles in situ. The use of an emulsion medium allowed the preparation of hairy nanoparticles with uniform size (coefficient of variation
