Narrow or Monodisperse, Physically Cross-Linked, and “Living” Spherical Polymer Particles by One-Stage RAFT Precipitation Polymerization

Abstract

Controlled preparation of narrow or monodisperse, physically cross-linked, and “living” spherical polymer particles by one-stage reversible addition–fragmentation chain transfer (RAFT) precipitation polymerization (RAFTPP) is described for the first time. The introduction of RAFT polymerization mechanism into precipitation polymerization system, together with the use of methacrylic acid (MAA) (capable of forming hydrogen bonding) as the monomer, allows ready generation of uniform spherical poly(MAA) (PMAA) particles with surface-bound “living” dithioester groups, easily tunable sizes, and low molecular weights in the absence of any cross-linking monomer. The polymerization parameters (i.e., monomer loading, molar ratio of the RAFT agent to free radical initiator, and polymerization temperature) showed much influence on the morphologies and yields of PMAA particles, and their simple adjustment allows fine-tuning of “living” PMAA particle sizes. The presence of dithioester groups on such PMAA particles was ...