Formation of ultrathin scarf-like micelles, ultrathin disk-like micelles and spherical micelles by self-assembly of polyurethane diblock copolymers

Controlling the shape and size of the nanomicelles attracts great interest and is still challenging. Herein, we synthesized a kind of diblock copolymers with the hydrophilic block (poly (ethylene glycol) methyl ether, PEG) and the core-forming block composed alternately by hydrophobic segments, hydrogen-bonding carbamates and pH-responsive groups. The synergy effect of the pH variation and the core-forming block length on the morphologies of the assemblies was well studied. Ultrathin scarf-like micelles, ultrathin disk-like micelles and spherical micelles were obtained by tailoring the pH values and the lengths of the core-forming blocks. The ultrathin scarf-like micelles and ultrathin disk-like micelles were proved to be composed of   a lamellar   bimolecular layer   of the block copolymers. This study will supply an effective method to fabricate well-defined nanostructures.