Novel Amphiphilic Multiarm, Starlike Coil–Rod Diblock Copolymers via a Combination of Click Chemistry with Living Polymerization
(7176–7183) Macromolecules 44 #18 (2011)
Pang et al of the Georgia Institute of Technology, Georgia and Iowa State University, Iowa, synthesized a series of novel amphiphilic 21-arm, starlike diblock copolymers, poly(acrylic acid)-b-poly(3-hexylthiophene) (PAA-b-P3HT), based on β-cyclodextrin (β-CD) with well-defined molecular architectures and ratio of two chemically distinct blocks, for the first time, via a combination of quasi-living Grignard metathesis method (GRIM), click reaction, and atom transfer radical polymerization (ATRP).  The starlike PAA-b-P3HT diblock copolymers consist of hydrophilic coil-like PAA cores and hydrophobic rodlike P3HT shells with narrow molecular weight distribution and well-defined molecular weight of each block.  Owing to the compact structure, the amphiphilic starlike PAA-b-P3HT formed a unimolecular micelle. Emulsion based on these novel amphiphilic starlike, coil–rod diblock copolymers were readily produced by cross-linking hydrophilic coil-like PAA cores with a bifunctional cross-linker, ethylenediamine.  (RDC 10/5/2011)

“Clickable” polymers via a combination of RAFT polymerization and isocyanate chemistry
(2771–2782)Journal of Polymer Science Part A: Polymer  Chemistry 49 #13 (2011)
Moraes, Maschmeyer and Perrier of the the University of Sydney, Australia, developed a one-pot, two-step polymerization towards synthesizing block co-polymers bearing reactive isocyanate functional groups.  Reversible addition fragmentation chain transfer (RAFT) polymerization is used to mediate the co-polymerization of isocyanate-bearing monomers dimethyl meta-isopropenyl benzyl isocyanate (TMI) and 2-isocyanatoethyl methacrylate (ICEMA) with styrene and methyl methacrylate (MMA), respectively. ICEMA was incorporated into the polymer at a faster rate than TMI and its unhindered isocyanate group was found to be more reactive than the hindered isocyanate group of TMI.  Both the TMI/styrene and the MMA/ICEMA systems maintain the reactivity of the isocyanate functionality, which was exploited by attaching representative hydroxyl-bearing small and large molecules as well as solid substrates to the block co-polymers. Thus, we demonstrate the versatility of the block co-polymer system as a basis for forming branched polymers or as grafts for a solid substrate.  (RDC 6/17/2011)