Harnessing the Interaction between Surfactant and Hydrophilic Catalyst To Control eATRP in Miniemulsion

In contrast to our previous report, it is now described that miniemulsion eATRP can be carried out with an anionic surfactant and a single, strongly hydrophilic catalyst. The obtained PBA was well-defined, with MWs matching theoretical values and low Đ. Chain extension experiments con firmed that chain-end functionality was very well retained. These results are in contrast with a previous paradigm that superhydrophobic catalysts are required for ATRP in dispersed media. In this work, the catalytic system was generated in situ by mixing commercially available reagents (NaBr, SDS, raditional copper catalysts). Only a few ppm of catalyst were present inside the monomer droplets. Polymer purification as simplified because, after crashing the miniemulsion, >99% of the hydrophilic catalyst was present in the aqueous phase. The ideal Cu catalyst has the following characteristics: (i) high activity, (ii) ability to form ion pairs with SDS, and (iii) stronger affinity for the surfactant when present in its Cu(II) oxidation state.