One-pot synthesis of well-defined amphiphilic alternating copolymer brushes based on POSS and their self-assembly in aqueous solution

Poly(maleimide isobutyl polyhedral oligomeric silsesquioxane-alt-vinylbenzyl polyethylene glycol) (P(MIPOSS-alt-VBPEG)) amphiphilic copolymer brushes with a sequence of alternating MIPOSS and polyethylene glycol (PEG) side chains were synthesized via ordinary radical polymerization and reversible addition-fragmentation transfer (RAFT) polymerization. A series of alternating copolymer brushes prepared by RAFT polymerization had a low polydispersity index (PDI) of less than 1.25. The thermal properties of these copolymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results displayed that the MIPOSS units could effectively enhance the thermal properties of the hybrid copolymers. The self-assembly behavior of the P(MIPOSS-alt-VBPEG) amphiphilic copolymer brushes in aqueous media was also studied by fluorescence spectrophotometry (FS), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results showed that these alternating copolymer brushes could form spherical aggregates in water.