The star block copolymers with polystyrene-block-poly(ethylene oxide) (PS-b-PEO) as side chains and hyperbranched polyglycerol (HPG) as core were synthesized by combination of atom transfer radical polymerization (ATRP) with the ''atom transfer nitroxide radical coupling'' (''ATNRC'') reaction. The multiarm PS with bromide end groups originated from the HPG core (HPG-g-(PS-Br) n ) was synthesized by ATRP first, and the heterofunctional PEO with a-2,2,6,6-tetramethylpiperidinyl-1-oxy group and x-hydroxyl group (TEMPO-PEO) was prepared by anionic polymerization separately using 4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy (HTEMPO) as parents compound. Then ATNRC reaction was conducted between the TEMPO groups in PEO and bromide groups in HPG-g-(PS-Br) n in the presence of CuBr and pentamethyldiethylenetriamine (PMDETA). The obtained star block copolymers and intermediates were characterized by gel permeation chromatography, nuclear magnetic resonance spectroscopy, fourier transform-infrared in detail. Those results showed that the efficiency of ATNRC in the preparation of multiarm star polymers was satisfactory ([90%) even if the density of coupling cites on HPG was high. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: [6754][6755][6756][6757][6758][6759][6760][6761] 2008

The copolymer of polystyrene‐block‐poly(ethylene oxide)‐block‐poly (tert‐butyl acrylate) (PS‐b‐PEO‐b‐PtBA) was prepared, the synthesis process involved ring‐opening polymerization (ROP), nitroxide‐mediated polymerization (NMP), and atom transfer radical polymerization (ATRP), and 4‐hydroxyl‐2,2,6,6‐tetramethylpiperidinyl‐1‐oxy (HTEMPO) was used as parent compound. The PEO precursors with α‐hydroxyl‐ω‐2,2,6,6‐tetramethylpiperidinyl‐1‐oxy end groups(TEMPO‐PEO‐OH) were first obtained by ROP of EO using HTEMPO and diphenylmethylpotassium (DPMK) as the coinitiator. The TEMPO at one end of PEO chain mediated the polymerization of St using benzoyl peroxide as initiator. The resultant PS‐b‐PEO‐OH reacted further with 2‐bromoisobutyryl bromide and then initiated the polymerization of tBA in the presence of CuBr and PMDETA by ATRP. The ternary block copolymers PS‐b‐PEO‐b‐PtBA and intermediates were characterized by gel permeation chromatography, Fourier transform infrared, and nuclear magnetic resonance spectroscopy in detail. Differential scanning calorimetry measurements confirmed that the PS‐b‐PEO‐b‐PtBA with PEO as middle block can weaken the interaction between PS and PtBA blocks, the glass transition temperature (Tg) for two blocks were approximate to their corresponding homopolymers comparing with the PEO‐b‐PS‐b‐PtBA with PEO as the first block. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2624–2631, 2008

The star graft copolymers composed of hyperbranched polyglycerol (HPG) as core and well defined asymmetric mixed ''V-shaped'' identical polystyrene (PS) and poly(tert-butyl acrylate) as side chains were synthesized via the ''click'' chemistry. The V-shaped side chain bearing a ''clickable'' alkyne group at the conjunction point of two blocks was first prepared through the combination of anionic polymerization of styrene (St) and atom transfer radical polymerization of tert-butyl acrylate (tBA) monomer, and then ''click'' chemistry was conducted between the alkyne groups on the side chains and azide groups on HPG core. The obtained star graft copolymers and intermediates were characterized by gel permeation chromatography (GPC), GPC equipped with a multiangle laser-light scattering detector (GPC-MALLS), nuclear magnetic resonance spectroscopy and fourier transform infrared. V

The amphiphilic A2B star‐shaped copolymers of polystyrene‐b‐[poly(ethylene oxide)]2 (PS‐b‐PEO2) were synthesized via the combination of atom transfer nitroxide radical coupling (ATNRC) with ring‐opening polymerization (ROP) and atom transfer radical polymerization (ATRP) mechanisms. First, a novel V‐shaped 2,2,6,6‐tetramethylpiperidine‐1‐oxyl‐PEO2 (TEMPO‐PEO2) with a TEMPO group at middle chain was obtained by ROP of ethylene oxdie monomers using 4‐(2,3‐dihydroxypropoxy)‐TEMPO and diphenylmethyl potassium as coinitiator. Then, the linear PS with a bromine end group (PS‐Br) was obtained by ATRP of styrene monomers using ethyl 2‐bromoisobutyrate as initiator. Finally, the copolymers of PS‐b‐PEO2 were obtained by ATNRC between the TEMPO and bromide groups on TEMPO‐PEO2 and PS‐Br, respectively. The structures of target copolymers and their precursors were all well‐defined by gel permeation chromatographic and nuclear magnetic resonance (1H NMR). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

The graft copolymers composed of “Y”‐shaped polystyrene‐b‐poly(ethylene oxide)2 (PS‐b‐PEO2) as side chains and hyperbranched poly(glycerol) (HPG) as core were synthesized by a combination of “click” chemistry and atom transfer radical polymerization (ATRP) via “graft from” and “graft onto” strategies. Firstly, macroinitiators HPG‐Br were obtained by esterification of hydroxyl groups on HPG with bromoisobutyryl bromide, and then by “graft from” strategy, graft copolymers HPG‐g‐(PS‐Br) were synthesized by ATRP of St and further HPG‐g‐(PS‐N3) were prepared by azidation with NaN3. Then, the precursors (Bz‐PEO)2‐alkyne with a single alkyne group at the junction point and an inert benzyl group at each end was synthesized by sequentially ring‐opening polymerization (ROP) of EO using 3‐[(1‐ethoxyethyl)‐ethoxyethyl]‐1,2‐propanediol (EEPD) and diphenylmethylpotassium (DPMK) as coinitiator, termination of living polymeric species by benzyl bromide, recovery of protected hydroxyl groups by HCl and modification by propargyl bromide. Finally, the “click” chemistry was conducted between HPG‐g‐(PS‐N3) and (Bz‐PEO)2‐alkyne in the presence of N,N,N′,N″,N”‐pentamethyl diethylenetriamine (PMDETA)/CuBr system by “graft onto” strategy, and the graft copolymers were characterized by SEC, 1H NMR and FTIR in details. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010