Synthesis and Direct Visualization of Block Copolymers Composed of Different Macromolecular Architectures

A novel approach toward the synthesis of block copolymers composed of architecturally different components, in this case, a nanoparticle covalently attached to a single linear coil is presented. By a synergistic combination of controlled radical polymerization, convergent dendrimer synthesis, and benzocyclobutene (BCB) cross-linking chemistry, strategies for the preparation of a variety of nanoparticle−coil copolymers were developed. Atomic force microscopy (AFM) was used to confirm the formation of architecturally differentiated block copolymers and enabled visualization of individual nanoparticles and their linear chain components for unambiguous characterization of the nanoparticle−coil structures. This confirmed the synthesis of the targeted nanostructure and revealed the dramatic effect that changes in macromolecular architecture can have on the morphology and assembly of these hybrid nanoparticle systems.