Synthesis of Soluble Silsesquioxane–Polythiophene Hybrid Copolymers with a Controlled Morphology

We report the synthesis of hybrid copolymers in which RAFT-synthesized poly(dimethylaminoethyl methacrylate)-b-polymethacrylate (PDMA-b-PMA) and poly(3,4-ethylenedioxythiophene) (PEDOT) were combined in a precise cluster core of deca-functionalized silsesquioxane via sequential click grafting and oxidative coupling polymerization. Controlled extension of the conjugated chains from the end functionality on the cage periphery was performed via a modified interfacial synthesis protocol, which yielded a soluble hybrid polythiophene-conjugated polymer without requiring the use of thiophene monomers that contain bulky solubilizing side chains. The obtained polymers were fully characterized via various techniques, including NMR, FTIR, UV–vis, and fluorescence spectroscopies as well as SEC and AFM measurements. The combination of the star-shaped architecture and interchain compositional heterogeneity allowed for the formation of a transparent, flexible, and electroactive polymer film. Thermal annealing induced an ordered nanostructure in the thin films, which may be related to the local interaction constraints, corresponding to the reduced π-stacking distance that facilitates hopping of electrons. On the basis of these promising results, these hybrid polythiophene-containing copolymers could find applications in imaging and chemosensing and in the design of flexible optoelectronics.