In Situ and Online Monitoring Polymerization-Induced Micellization

The polymerization-induced micellization of poly(ethylene oxide)-b-poly(styrene-alt-maleic anhydride) (PEO-b-P(S-alt-MAn)) in CHCl₃ was monitored in situ by laser light scattering. Reversible addition−fragmentation chain transfer (RAFT) polymerization was used to grow the P(S-alt-MAn) block onto the PEO macromolecular chain transfer agents (macro-CTAs) at 55 °C. The whole process underwent three stages over time: the induction period, the formation of loose aggregates, and the formation of micelles. The polymerization process and the micellization process were affected mutually: the increase in the degree of polymerization induced the micellization of PEO-b-P(S-alt-MAn); meanwhile, the formation of core−shell micelles retarded the polymerization rate. At higher polymer concentrations, the mutual effect was even stronger, where smaller size micelles with higher density were obtained.