One‐Dimensional Helical Nanostructures from the Hierarchical Self‐Assembly of an Achiral “Rod−Coil” Alternating Copolymer

Abstract The self‐assembly of alternating copolymers (ACPs) has attracted considerable interest due to their unique alternating nature. However, compared with block copolymers, their self‐assembly behavior remains much less explored and their reported self‐assembled structures are limited. Here, the formation of supramolecular helical structures by the self‐assembly of an achiral rod−coil alternating copolymer named as poly(quarter(3‐hexylthiophene)‐ alt ‐poly(ethylene glycol)) (P(Q3HT‐ alt ‐PEG)), is reported. The copolymer exhibits an interesting hierarchical self‐assembly process, driven by the π − π stacking of the Q3HT segments and the solvophobic interaction of the alkyl chains in tetrahydrofuran (THF)−isopropanol mixed solvents. The copolymer first self‐assembled into thin nanobelts with a uniform size, then grows to helical nanoribbons and eventually twisted into helical nanowires with an average diameter of 25 ± 9 nm and a mean pitch of 80 ± 10 nm. Dissipative particle dynamics (DPD) simulation supports the formation course of the helical nanowires. Furthermore, the addition of ( S )‐ethyl lactate and ( R )‐ethyl lactate in the self‐assembly of P(Q3HT‐ alt ‐PEG) results in the formation of left‐handed and right‐handed chiral nanowires, respectively, demonstrating the tunability of the chirality of the helical wires. This study expands the library of ordered self‐assembled structures of ACPs, and also brings a new strategy and mechanism to construct helical supramolecular structures.