Radical Ring-Opening Copolymerization-Induced Self-Assembly (rROPISA)

Abstract

Radical ring-opening copolymerization-induced self-assembly (rROPISA) was performed by copolymerizing benzyl methacrylate and cyclic ketene acetals (CKA), such as 2-methylene-4-phenyl-1,3-dioxolane or 5,6-benzo-2-methylene-1,3-dioxepane, in heptane at 90 °C by reversible addition-fragmentation chain transfer (RAFT) polymerization from a poly(lauryl methacrylate) macro-RAFT agent. The chain lengths of both the solvophilic macro-RAFT agent and the solvophobic block, together with the initial amount of CKA, were independently varied to achieve various compositions. The amount of CKA in the copolymers ranged from 4 to ∼40 mol % by adjusting the monomer stoichiometry, leading to nearly complete degradation for CKA contents above ∼15 mol %. rROPISA led to stable nanoparticles in all cases, ranging from 40 to 500 nm in diameter, depending on the experimental conditions, as assessed by dynamic light scattering and transmission electron microscopy. Low average diameters and very narrow particle size distributions ...