Recent Progress on Hyperbranched Polymers Synthesized via Radical-Based Self-Condensing Vinyl Polymerization

This short review article summarizes recent reports on using controlled radical polymerization (CRP) of inimers (compounds containing initiating group and vinyl group in one molecule) or transmers (compounds containing chain transfer group and vinyl group in one molecule) for the synthesis of hyperbranched polymers. These inimers and transmers that carry numerous functional groups could be homopolymerized, i.e., self-condensing vinyl polymerization, or copolymerized with monovinyl monomers, i.e., self-condensing vinyl copolymerization, using atom transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP) or reversible addition fragmentation chain transfer (RAFT) polymerization techniques, producing hyperbranched polymers and hyperstar polymers with tunable molecular weights, compositions and degree of branching. Recent reports that attempted different strategies to regulate polymer–polymer reactions were introduced, demonstrating possible syntheses of hyperbranched polymers with better defined structures and relatively low molecular weight dispersity. Finally, several CRP-produced hyperbranched polymers were discussed on their applications for encapsulation of guest molecules, nanomedicine, diagnostic imaging and catalysis.