RAFT-mediated polymerization-induced self-assembly of cholic acid-derived monomer

This contribution used polymerization-induced self-assembly (PISA) to prepare PHEA- b -PCAE block copolymers that self-assemble simultaneously, forming spheres or vesicles. Poly(2-hydroxyethyl acrylate) (PHEA) was chain-extended with cholic acid-derived monomer (CAE) via RAFT emulsion polymerization in a mixture of ethanol/water at 70 °C. The formation of self-assemblies was only observed when the proportion of water in the mixture was between 56 to 45% (at a solid content of 8 or 11%). Furthermore, under these conditions, the polymerizations proceed fast, reaching high conversions. As the water content decreased in the reaction medium, the conversion decreased drastically. In contrast, when the polymerization was conducted in pure ethanol, only 13% conversion was achieved in 5 h. The RAFT emulsion polymerization of CAE exhibits an improved polymerization rate compared to the solution polymerization. Moreover, the observed morphology depends on the solids content (for ethanol/water 45:55, v/v): vesicles (11% w/w) and spheres (8% w/w). The vesicles were treated with N -(hydroxymethyl)acrylamide (HMAm) as a cross-linker which caused a considerable increase in their size.