Liquid Crystal Promoted\nSelf-Assembly of Statistical\nCopolymers into Diverse Nanostructures with Precise Dimensions

In\nboth natural and synthetic systems, the segregation\nof multicomponent\nentities is vital for regulating functions and the ultimate usage\nof materials. To accomplish the desired properties via nanosegregation\nor microphase separation, great effort is usually demanded in the\nsynthesis. For example, microphase-separated block copolymers rely\non the delicate controlled/living polymerization of different monomers\nin sequence. Here, we demonstrate that a facile one-pot copolymerization\ncan generate statistical side-chain copolymers exhibiting well-defined\nand diverse nanostructures. Two hemiphasmidic (or wedge-shaped) cyclooctene\nmonomers were designed, differing in the peripheral tails of the wedges\n(dodecyl vs. tetraethylene glycol), with lengths of ca. 1 nm. When\ncombining the two monomers together, the statistical copolymers can\nshow columnar liquid crystal (LC) phase and microphase-separated structures\nof the two monomers, including sphere, cylinder, double gyroid, and\nlamella. To the best of our knowledge, this is the first time the\ngyroid phase has been achieved in statistical copolymers. We further\ndemonstrate that changing the side chains to calamitic (or rod-like)\nmesogens or the backbone to less flexible polynorbornene, the statistical\ncopolymers can also undergo microphase separation of the side chains.\nThe intrinsic self-assembly scheme of statistical copolymers with\nmesogenic side chains, which are chemically accurate, affords the\nresultant nanostructures with precise periodicities at the 10- or\nsub–10-nm scale. Given the small chemical difference between\nthe side-chain tails, microphase separation is promoted by the anisotropic\npacking of mesogens. It is validated that the statistical side-chain\nLC copolymers can be a versatile platform for creating nanostructured\nmaterials with tailored functionalities.