Aqueous-Phase Ring-Opening Metathesis Polymerization-Induced Self-Assembly

We report aqueous-phase Ring-Opening Metathesis Polymerization-Induced Self-Assembly (ROMPISA) for forming well-defined micellar polymer nanoparticles at room temperature and high solids concentration (20 w/w%). This is achieved with a new polymerization initiator, in the form of a water-soluble cationic Hoveyda-Grubbs second generation catalyst. This reaction was used in water to produce diblock copolymers from norbornenyl monomers, which then self-assemble into myriad nanostructure morphologies for which a phase diagram was constructed. Additionally, the living nature of the polymerization initiated by the aqueous initiator was confirmed, as shown by kinetic evaluation under mild conditions in water.