Synthesis of well-defined dendritic hyperbranched polymers by iterative methodologies using living/controlled polymerizations

This review presents firstly the synthesis of various dendritic hyperbranched polymers with well-defined structures by generation-based growth methodologies using living/controlled polymerization. Secondly, the synthesis of dendritic hyperbranched poly(methyl methacrylate)s (PMMAs) and their functionalized block copolymers using a novel iterative methodology is described. The methodology involves a two-reaction sequence in each iterative process: (a) a linking reaction of alpha-functionalized living anionic PMMA with tert-butyldimethylsilyloxymethylphenyl (SMP) groups with benzyl bromide (BnBr)-chain-end-functionalized polymer and (b) a transformation reaction of the SMP groups into BnBr functions. This reaction sequence is repeated several times to construct high-generation (maximum seventh generation) dendritic hyperbranched polymers. Similar branched architectural block copolymers have also been synthesized by the same iterative methodology using other a-functionalized living anionic polymers. Surface structures of the resulting dendritic hyperbranched block copolymers composed of PMMA and poly(2-(perfluorobutyl)ethyl methacrylate) segments have been characterized using X-ray photoelectron spectroscopy and contact angle measurements. Solution behaviors of dendritic hyperbranched PMMAs with different generations and branch densities are discussed based on their intrinsic viscosities, g' values and R-h values. (c) 2007 Society of Chemical Industry.