Self-assembly of POSS-containing block copolymers: Fixing the hierarchical structure in networks

A series of P(MMA-co-GMA)-b-PMAPOSS block copolymers (BCPs) were synthesized by ATRP. The BCPs contain POSS (polyhedral oligomeric silsesquioxane) as a pendant unit on a particular polymer block chain. In selective solvents, the BCPs self-assemble to form ordered micellar-like structures. Spherical, cylindrical or vesicle-like morphologies were produced by tuning the BCP and mixed solvent compositions. Crosslinking of the BCP by the reaction of the glycidyl groups in the P(MMA-co-GMA) block of the micelle shell (GMA = glycidyl methacrylate) with a diamine results in a long-range structure ordering. The hexagonally packed cylindrical arrangement of the BCP networks was revealed by SAXS and TEM. The hierarchical, ordered structure of the POSS-containing hybrids was fixed by crosslinking. In addition, transient physical gels were prepared from triblock copolymers with outer MAPOSS blocks, and their rheological behavior was investigated.