Synthesis of soap-free emulsion with high solid content by differential dripping RAFT polymerization-induced self-assembly

Polymerization induced self-assembly (PISA) has been a facile and effective approach to prepare highly concentrated block copolymer nano-objects in situ. In this work, a soap-free emulsion with high solid content (60%) was successfully prepared in a semi-batch monomer addition manner. High monomer conversion can also be obtained by adjusting the dripping time. At first, a hydrophilic polymer, poly(poly(ethylene glycol) monomethyl ether methacrylate) (PPEGMA) was synthesized at almost complete monomer conversion in order to be used as a macroRAFT agent without any purification in the following step. Then PPEGMA was chain extended by the second monomer, methyl methacrylate (MMA), added at a very slow rate to form diblock copolymers and further self-assembled into nanoparticles in situ. The resulting latexes were very stable and the particle sizes remained at the nanoscale.