Dendrimers and hyperbranched polymers (HPs) have demonstrated a wide array of potential applications, including cosmetics, drug delivery, and lubricants. A variety of synthetic methods have been developed to realize dendrimers and HPs as well as their hybrid derivatives. In contrast to dendron-type polymers that require multi-step syntheses, HPs are more synthetically accessible as they can be prepared through single-step strategies. Development of a site-specific initiation is yet needed to enable efficient and precise incorporation of HPs for the synthesis of hybrid materials. Yamago and coworkers recently reported a chain-growth type HPs synthesis. A vinyl telluride monomer of a hierarchical reactivity was copolymerized with methyl acrylate under organotellurium-mediated living radical polymerization (TERP) condition, resulting in HPs with controlled degree of polymerization and branching.<i> Inspired by this work, we hypothesize that similar concept could be translated to atom transfer radical polymerization (ATRP) and HPs containing diverse functional side-groups can be grafted from target sites in a controlled manner. As shown in scheme 1, we copolymerized <i>a</i>-bromo vinyl containing monomer (AB) with other common monomers (A), e.g., acrylate and styrene, under copper-catalyzed ATRP conditions. HPs grown exclusively from ATRP initiator (B*) were realized. The carbon-bromo bond of AB cannot be activated by copper catalyst until the vinyl group is polymerized in to a polymer chain, and a branching point in the polymer chain is thus generated upon the incorporation of an AB monomer. By tuning the feeding ratio of AB and A, HPs with different branching density were obtained.

Chain-growth type (hyper)branched radical copolymerization: A promising approach to functional materials with controlled incorporation of branching motifs

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.