Synthesis of Block Copolymer Particles by One-Pot, Two-Step Dispersion Reversible Chain Transfer Catalyzed Polymerization (Dispersion RTCP) in Supercritical Carbon Dioxide

Direct synthesis of micrometer-sized, poly(methyl methacrylate)-block-polystyrene (PMMA-b-PS) particles by one-pot, two-step dispersion reversible chain transfer catalyzed polymerization (dispersion RTCP) with nitrogen catalyst was successfully demonstrated in supercritical carbon dioxide (scCO₂). The molecular weight distribution was clearly shifted to higher molecular weight side compared to that of PMMA-I prepared in the first step, indicating the successful synthesis of the block copolymer. This was supported by thin-layer chromatographic result. The blocking efficiency, which was obtained from the two number-distribution curves of molecular weight measured from gel permeation chromatography with dual detectors (refractive index and ultraviolet), was 87%.