High Resolution Cryo-TEM Structure of Fiber-like Micelles with a Crystalline Core

Abstract Seeded growth of crystallizable block copolymers and π-stacking molecular amphiphiles in solution using the living crystallization-driven self-assembly (CDSA) method is attracting growing interest as a route to uniform 1D and 2D core–shell micellar nanoparticles of controlled size with a range of potential applications. Although experimental evidence indicates that the process proceeds via an epitaxial growth mechanism and that the resulting crystalline core is highly ordered, direct observation of the crystal lattice has not been successful. Herein we report the results of high-resolution cryo-TEM studies that permit direct observation of both the solvated corona chains and the crystalline core from studies of frozen solution of nanofiber micelles prepared by living CDSA. Together with complementary characterization data, this provides key insight into the structure of the corona and the detailed arrangement of the polymer chains in the crystalline micellar nanofiber core.