Synthesis and Characterization of Helix-Coil Diblock Copolymers with Controlled Supramolecular Architectures in Aqueous Solution

The design and synthesis of suitable block copolymers, such as those consisting of both flexible components and rigid components, as building blocks for highly ordered supramolecular architectures have attracted considerable attention in the past several decades. The resulting supramolecular structures can potentially offer various functionalities by means of their photophysical, electrochemical, or biological properties through the rod blocks. Due to the combined results of the orientation of the rod block and the microphase separation of the two incompatible blocks, rod-coil block copolymers exhibit distinct self-assembling behaviors and morphologies compared to their coil-coil counterparts. The incorporation of helical chains as the rigid-rod component in rod-coil copolymers represents a unique approach to creating novel supramolecular architectures. In the studies of polystyrene-block-poly(isocyanodipeptide) in aqueous solution, the chirality of the macromolecules results in the formation of superstructures that have a helical sense bias opposite to that of the constituent block copolymers. It was believed that the helical conformation Summary: A series of helix-coil diblock copolymers based on poly(ethylene oxide) and optically active helical poly{(þ)-2,5-bis[40-((S)-2-methylbutoxy)phenyl]styrene} (PMBPS) were synthesized via atom transfer radical polymerization (ATRP). The synthetic methodology permitted straightforward preparation of the diblock copolymers with relatively low polydispersities and a broad range of compositions and molecular weights. Depending on the composing block length and the initial concentration, the copolymers self-assembled into different supramolecular structures in aqueous solution, including sphericalmicelles, vesicles,multilamellar vesicles, large compound vesicles, and tubules.