Solution Self-Assembly of Block Copolypeptoids with a Crystallizable Core-Forming Block

In this study, we investigate the solution self-assembly of coil-crystalline diblock copolypeptoids with one polypeptoid block having long n-alkyl side chains. Poly(N-methyl glycine)-b-poly(N-decyl glycine) (i.e. PNMG-b-PNDG) with lower volume fraction of the crystalline PNDG blocks were found to slowly self-assemble into one-dimensional long worm-like nanofibrils in methanol, which is induced by the crystallization of core-forming PNDG. Upon increasing volume fraction of PNDG, the final micellar morphology changed from worm-like nanofibrils to rigid short nanorods and then two-dimensional nanosheets. The molecular arrangement and self-assembly pathways of these anisotropic nanostructures were investigated by a combination of X-ray/neutron scattering and microscopic techniques to understand the underlying assembly mechanism. We believe the relationship between chemical composition, micellar morphology and self-assembly pathway provided here would not only benefit the rational design of polypeptoid-based nanostructures with tunable size, shape and morphology, but also shed lights on the crystallization-driven self-assembly of comb-shaped polymers bearing long aliphatic side chains in general.