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 α‐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 α‐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.