Effects of stirring rate on morphology of aqueous RAFT emulsion PISA-derived block copolymer nanoparticles

The influence of stirring rate on nanoparticle morphology in aqueous RAFT emulsion PISA has been investigated using the macroRAFT agents poly(poly(ethylene)glycol methyl ether acrylate)-TTC and poly(poly(ethylene glycol) methyl ether methacrylate)-TTC chain extended with styrene/n-butyl acrylate (copolymer) and methyl methacrylate (MMA), respectively. The influence of temperature was first investigated by conducting polymerizations at 50 degrees C and 70 degrees C for the MMA system, revealing that formation of high-order morphologies is facilitated at 70 degrees C. The influence of stirring rate was explored for both systems, showing that the extent of influence depends on the polymerization temperature. At 50 degrees C, high-order morphologies were obtained only at moderate stirring rate whereas at 70 degrees C, high-order morphologies were observed across a much wider range of stirring rates. The present results demonstrate that both polymerization temperature and stirring rate can significantly affect the self-assembly process in PISA. The influence of stirring rate on nanoparticle morphology in aqueous RAFT emulsion PISA has been investigated.