TEMPO-Mediated emulsion polymerization

While miniemulsion polymerization has proven to be well-suited for conducting living/controlled radical polymerizations, emulsion polymerizations have proven to be far more challenging. Ab initio emulsion polymerizations, in which monomer droplets are present during polymerization, have thus far not been successful with TEMPO-mediated polymerizations, as a result of colloidal instability and coagulum formation. By selectively inhibiting polymerization in the monomer droplets, it is demonstrated that droplet polymerization is responsible for the formation of large (>1 mu m) particles that can lead to coagulum formation. Furthermore, we show that coagulum-free latexes can be produced using a TEMPO-mediated ab initio emulsion polymerization by suppressing droplet polymerization.