Synthesis of Organic/Inorganic Polyhedral Oligomeric Silsesquioxane-Containing Block Copolymers via Reversible Addition–Fragmentation Chain Transfer Polymerization and Their Self-Assembly in Aqueous Solution

Polyhedral oligomeric silsesquioxane (POSS)-containing homopolymers (PHEMAPOSS) with a high degree of polymerization (DP) were synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization. PHEMAPOSS was used as a macro-RAFT agent to construct a series of amphiphilic diblock copolymers, PHEMPOSS-<i>b</i>-PMAA (poly (methyl methacrylate)), which possessed a different length of hydrophilic chains. The self-assembly behavior of PHEMPOSS-<i>b</i>-PMAA in aqueous solution was studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), and dynamic light scattering (DLS), respectively. The results showed that PHEMAPOSS₄₅-<i>b</i>-PMAA₅₂₃ forms typical core–shell spherical micelles where the hydrophobic PHEMAPOSS blocks as the core and hydrophilic PMAA blocks as the shell. With increasing PMAA chain length, PHEMAPOSS₄₅-<i>b</i>-PMAA₁₁₇₃ with a longer PMAA chain self-assembled into irregular aggregates with POSS moieties dispersed in the aggregates. On the other hand, PHEMAPOSS₄₅-<i>b</i>-PMAA₃₀₈ with a shorter hydrophilic PMAA chain could self-assemble into a dendritic cylinder structure