Organizations: Research Council of Lithuania [MIP-54/2015]
Synthesis of coil-brush, brush-coil-brush and coil-brush-coil polystyrene-based di-and tri-block copolymers containing poly(acrylic acid) (PAA) side chains via RAFT polymerization is reported demonstrating the effect of RAFT CTA on kinetics and the structure of the resulting polymers. Several mono-and bi-functional RAFT CTAs were used which enabled the synthesis of target copolymers with a relatively low dispersity index and the desired DP of PAA side chains. Polystyrene-based anionic brush copolymers were studied by SEC with triple detection, H-1 NMR spectroscopy, TEM, DLS, and water contact angle measurements. According to the wettability of the copolymer films, the most hydrophilic copolymers were of coil-brush and brush-coil-brush structures, especially with longer PAA chains. Polystyrenebased anionic brush copolymers in mixed solutions of DO and water formed micelles and, at a larger amount of water, micellar aggregates with a hydrodynamic diameter of 500-1000 nm. The shape and size of the micelles were dependent on the location of brush and linear blocks; the formation of micellar aggregates was more prevalent for the brush copolymers with short PAA side chains. This study provides an efficient approach for the preparation of polystyrene-based brush copolymers of various structures whose properties could be tuned by the use of different RAFT CTAs.
