Incompletely condensed, fluorinated polyhedral oligomeric silsesquioxane with the highly reactive group of trisodium silanolate was used for the synthesis of an initiator for atom transfer radical polymerization. The initiator was applied to solution polymerization of methyl methacrylate (MMA) in the presence of a copper complex. The polymerization proceeded in a living fashion, providing tadpole-shaped polymers with an “inorganic head” of polyhedral oligomeric silsesquioxane (POSS) and an “organic tail” of well-defined PMMA. A blend film composed of the tadpole-shaped polymer and a matrix PMMA was annealed at 180 °C for 5 days and then analyzed by neutron reflectometry, X-ray photoelectron spectroscopy, and contact angle measurement. These analyses revealed that the tadpole-shaped polymer was preferentially populated at the air/polymer interface, and the outermost layer of the film was almost completely covered by the POSS heads. This was mainly due to the low surface free energy of the fluorinated POSS moiety. Owing to this unique structure, the blend film showed strong resistance against Ar+ ion etching, despite the overall POSS content was only 2 wt %.

Incompletely condensed polyhedral oligomeric silsesquioxane (POSS) with the highly reactive group of trisodium silanolate was used for the synthesis of two initiators for atom transfer radical polymerization, one with a 2-bromoisobutyl group and the other with a chlorosulfonyl group. These initiators were applied to solution polymerizations of styrene and methyl methacrylate in the presence of a copper complex. In both systems, polymerization proceeded in a living fashion, as indicated by the first-order kinetics of monomer consumption, the evolution of molecular weight in direct proportion to monomer conversion, the good agreement of molecular weight with the theoretical one, and the low polydispersity, thus providing tadpole-shaped polymers with an “inorganic head” of POSS and an “organic tail” of well-defined polymer. Thermogravimetric and differential scanning calorimetric studies showed that both thermal degradation and glass transition temperatures of the organic/inorganic hybrid polymers with molecular weights up to about 20 000 were enhanced as compared to those of model polymers without the POSS moiety.