Amphiphilic H-shaped [poly(ethylene oxide)](3)-polystyrene-[poly(ethylene oxide)](3)(PEO3-PS-PEO3) copolymer was synthesized by 2-methyl-2-nitrosopropane (MNP) induced single electron transfer nitroxide radical coupling (SETNRC) using PEO3-(PS-Br) as a single precursor. First, the A(3)B star-shaped precursor PEO3-(PS-Br) was synthesized by atom transfer radical polymerization (ATRP) using three-arm star-shaped PEO3-Br as macro-initiator. Then, in the presence of Cu(I)Br/Me6TREN, the bromide group at PS end was sequentially transferred into carbon-centered radical by single electron transfer and then nitroxide radical by reacting with MNP in mixed solvents of dimethyl sulfoxide (DMSO)/tetrahydrofuran (THF), and in situ generated nitroxide radical could again capture another carbon-centered radical by fast SETNRC to form target PEO3-PS-PEO3 copolymer. The MNP induced SETNRC could reach to a high efficiency of 90% within 60 min. After the product PEO3-PS-PEO3 was cleaved by ascorbic acid, the SEC results showed that there was about 30% fraction of product formed by single electron transfer radical coupling (SETRC) between carbon-centered radicals. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 2811-2817, 2011