Expanding the toolbox of controlled/living branching radical polymerization through simulation-informed reaction design

Abstract

•A controlled/living branching polymerization was achieved •Mechanistic studies and kinetic simulations guided the reaction optimization •Branched polymers were synthesized from a broad range of vinyl monomers Branched polymers with superior mechanical, photonic, and electrical properties have shown their growing advantages in biomedical applications, water treatment, and catalysis. Anchoring branched functional motifs onto select molecular-/nano-objects introduces structural hierarchy as well as combined and enhanced properties. To realize efficient grafting of branched functional polymers, a controlled chain-growth branching polymerization is desirable but remains underexplored. In this article, the chain-growth process was achieved by copolymerizing α-haloacrylate with conventional vinyl monomers via atom transfer radical polymerization. We conducted systematic mechanistic studies to obtain an optimal profile of the polymerization conditions, where an activator regeneration approach was employed. Assisted by kinetic simulations, a variety of vinyl monomers, including acrylates, styrene, acrylonitrile, and acrylamides, were successfully copolymerized with α-haloacrylate with high monomer conversion to produce well-defined branched polymers with tunable degrees of branching. The impact of controlled branching on the thermoresponsive properties was studied using the synthesized poly(N-isopropylacrylamide). Branched polymers with superior mechanical, photonic, and electrical properties have shown their growing advantages in biomedical applications, water treatment, and catalysis. Anchoring branched functional motifs onto select molecular-/nano-objects introduces structural hierarchy as well as combined and enhanced properties. To realize efficient grafting of branched functional polymers, a controlled chain-growth branching polymerization is desirable but remains underexplored. In this article, the chain-growth process was achieved by copolymerizing α-haloacrylate with conventional vinyl monomers via atom transfer radical polymerization. We conducted systematic mechanistic studies to obtain an optimal profile of the polymerization conditions, where an activator regeneration approach was employed. Assisted by kinetic simulations, a variety of vinyl monomers, including acrylates, styrene, acrylonitrile, and acrylamides, were successfully copolymerized with α-haloacrylate with high monomer conversion to produce well-defined branched polymers with tunable degrees of branching. The impact of controlled branching on the thermoresponsive properties was studied using the synthesized poly(N-isopropylacrylamide).