Surfactant-Ligand Design for ab Initio Emulsion Atom Transfer Radical Polymerization

We report an ab initio emulsion atom transfer radical polymerization (ATRP) based on micellar nucleation. A surfactantligand (SL) was designed and synthesized for this purpose. The SL design was an amphiphilic macromolecule, and it acted as the surfactant for micelle formation and as the ligand for ATRP catalyst. The micelles were converted into to polymer particles with both water-soluble and oil-soluble initiators. The micellar nucleation mechanism was confirmed by the growth of polymer particles during polymerization, in comparison to a control experiment without SL addition. It was also found that diffusion-controlled deactivation inside particles occurred, which broadened the polymer molecular weight distribution. Adding a small amount of free catalyst significantly improved the molecular weight control. The polymers resulting from the ab initio emulsion ATRP were proven living by chain extension experiments.