A Novel Chain-Growth CuAAC Polymerization: One-pot Synthesis of Dendritic Hyperbranched Polymers with Well-Defined Structures

Abstract

This highlight presents an overview of our recent achievements on developing a chain-growth copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization of multifunctional AB m (m ≥ 2) monomers to produce structurally defined hyperbranched polymers in one pot. The chain-growth mechanism is attributed to the dedicate complexation between copper(I) catalyst and triazole groups that confine the copper catalyst in the polymers and selectively favor the polymer-monomer reaction rather than the monomer-monomer reactions. The living nature of this CuAAC polymerization was extensively explored to demonstrate the intriguing features of multibatch addition of various AB 2 monomers to produce hyperbranched polymers with high molar mass, low dispersity, core-shell segmented structures, and tunable solubility. 1 Background 2 Development of Living Chain-Growth CuAAC Polymerization 3 Functionalization and Segmented Structure in Hyperbranched Polymers 4 Conclusion Key words CuAAC click reactions, hyperbranched polymers, chaingrowth polymerization, high degree of branching, narrow molar-mass distribution BackgroundHyperbranched polymers, as an important category of soft nanomaterials, are often considered analogues of dendrimers due to their similar three-dimensional arborescent structures, high density of dendritic structural units, and multiple periphery groups. [1][2][3] These structural characteristics not only endow the polymers various intriguing physical properties, such as high shear resistance, low viscosity in the states of melt and solution, but also find them a variety of applications ranging from lubricant additives to catalysts and nanomedicines. 4Xiaosong Cao (left) obtained his BSc and MSc degrees at Wuhan University. In 2013, he joined the research group of Prof. Gao to pursue his PhD in organic chemistry at the University of Notre Dame. His research focuses on new polymerization methodology, synthesis of topological polymers with precise structure, and the relationship study between structure and properties in polymers. Dr. Yi Shi (right) obtained his BSc and MSc degrees at Xiangtan University and his PhD at Institute of Chemistry, Chinese Academy of Sciences (ICCAS) in 2013. After his graduation, he joined Prof. Gao's group in the Department of Chemistry and Biochemistry at the University of Notre Dame as a postdoctoral research associate. His research at Notre Dame is developing a new method that can achieve one-pot synthesis of hyperbranched polymers with high molar masses, low dispersity, and segmented dendritic structures as well as their potential applications. Dr. Haifeng Gao (middle) obtained his BSc and MSc degrees at Fudan University in China and his PhD at Carnegie Mellon University in 2008. After two years of postdoctoral experience at the University of California Berkeley, Dr. Gao started his independent career in 2011 at the University of Notre Dame, where he is currently an Assistant Professor in the Department of Chemistry and Biochemistry. Dr. Gao's research focuses on the design and synth...

Polylactic-Containing Hyperbranched Polymers through the CuAAC Polymerization of Aromatic AB2 Monomers

“…The first reports on the construction of polytriazole-based HPs through the homopolymerization of AB 2 monomers were explored by the Voit and Li groups, respectively [43,44]. More recently, Gao and co-workers reported the CuAAC living chain-growth polymerization of AB 2 monomers for producing HPs with a controlled structure and low Ð [45][46][47]. Our group have used a CuAAC polymerization of AB 2 monomers from 2,2-bis(hydroxymethyl)propionic acid, in which the distance between the polymerizable groups was systematically changed and the effect on the DBs was studied [48].…”

Stochastic Simulation of Controlled Radical Polymerization Forming Dendritic Hyperbranched Polymers

“…Some control over the HBP structure was achieved by using special polymerization conditions, such as stopping the polymerization at low monomer conversion, slow monomer addition, [16] or the use of monomer confinement under microemulsion polymerization conditions. [17] Recently, Yokozawa [18,19] and Gao [20,21] reported the controlled synthesis of HBPs by condensation polymerization using specially designed AB 2 monomer with defined reaction conditions. However, no general method has been realized so far.…”