Predictive Phase Diagrams for RAFT Aqueous Dispersion Polymerization: Effect of Block Copolymer Composition, Molecular Weight, and Copolymer Concentration

TLDR: Polymerization-induced self-assembly (PISA) of poly(glycerol monomethacrylate)-poly(2-hydroxypropyl methACrylate) (PGMA-PHPMA) diblocks is conducted using a RAFT aqueous dispersion polymerization formulation at 70 °C as discussed by the authors.

Abstract: Polymerization-induced self-assembly (PISA) of poly(glycerol monomethacrylate)–poly(2-hydroxypropyl methacrylate) (PGMA–PHPMA) diblocks is conducted using a RAFT aqueous dispersion polymerization formulation at 70 °C. Several PGMA macromolecular chain transfer agents (macro-CTAs) are chain-extended using a water-miscible monomer (HPMA): the growing PHPMA block becomes increasingly hydrophobic and hence drives in situ self-assembly. The final copolymer morphology in such PISA syntheses depends on just three parameters: the mean degree of polymerization (DP) of the PGMA stabilizer block, the mean DP of the PHPMA core-forming block, and the total solids concentration. Transmission electron microscopy is used to construct detailed diblock copolymer phase diagrams for PGMA DPs of 47, 78, and 112. For the shortest stabilizer block, there is essentially no concentration dependence: spheres, worms, or vesicles can be obtained even at 10% w/w solids simply by selecting the DP of the PHPMA block that gives the appr...