Synthesis and self-assembly of bottlebrush diblock copolymers

Bottlebrush copolymers have shown promise as building blocks for self-assembled nanomaterials due to their reduced chain entanglement relative to linear polymers and their ability to self-assemble with remarkably low critical micelle concentrations (CMCs). Concurrently, the preparation of bottlebrush polymers from organic electronic materials has recently been described, allowing multiple optoelectronic functions to be incorporated along the length of single bottlebrush strands. Here we successfully synthesized well-defined bottlebrush diblock copolymers containing soluble n-butyl acrylate blocks and carbazole-based organic semiconductors with control over the backbone length ratio. Then the successful incorporation of highly fluorescent dye molecules into the BBCP was achieved by using the CzBA polymer as an organic semiconductor host to facilitate energy transfer. We also describe the self-assembly of these molecular bottlebrushes, which self-assemble in selective solvent to give spherical micelles with CMCs below 54 nM. These narrowly dispersed structures were stable in solution at high dilution over periods of months, and could further be functionalized with fluorescent dyes to give micelles with quantum yields of unity. These results demonstrate that bottlebrush-based nanostructures can be formed from organic semiconductor building blocks, opening the door to the preparation of fluorescent or redox-active micelles from giant polymeric surfactants.Science, Faculty ofChemistry, Department ofGraduat