Self-assembly of thioether-based diblock copolymers: a comparative study of linear and bottlebrush architectures†

Amphiphilic diblock copolymers are widely studied for their ability to self-assemble into diverse nanostructures for various applications. Linear-linear diblock copolymers and linear-bottlebrush diblock copolymers exhibit distinct self-assembly due to differences in their molecular architecture. In this study, linear poly(ethylene glycol) (PEG) was used as the solvophilic block, and poly(2-(methylthio)ethyl methacrylate) (MTEMA, a thioether-containing polymer), was used as the solvophobic block to generate block copolymers where PMTEMA was either also a linear (LL) or a bottlebrush (LB) block. Comparing both architectures revealed differences in their self-assembly in aqueous environments. LL formed vesicles with broad size distributions while LB produced relatively uniform particles with ordered internal morphology, as confirmed by small-angle X-ray scattering (SAXS) and electron microscopy. The polymer particles could further be disassembled through an oxidizing agent which in turn allowed them to be used for oxidation-triggered release studies.