Synthesis of Core-Shell Polymer Particles in Supercritical Carbon Dioxide via Iterative Monomer Addition

A new, robust methodology for the synthesis of polystyrene-poly(methyl methacrylate) (PS-PMMA) core-shell particles using seeded dispersion polymerisation in supercritical carbon dioxide is reported, where the core-shell ratio can be controlled predictably via manipulation of reagent stoichiometry. The key development is the application of an iterative addition of the MMA shell monomer to the pre-prepared PS core. Analysis of the materials with differing core-shell ratios indicate that all are isolated as single particle populations with distinct and controllable core-shell morphologies