Syntheses and characterizations of the multiple morphologies formed by the self-assembly of the semicrystalline P4VP-b-PCL diblock copolymers

A series of semicrystalline diblock copolymers of poly(4-vinylpyridine-b-ɛ-caprolactone) (P4VP-b-PCL) have been synthesized by the living ROP of CL followed by the TEMPO polymerization of 4-VP. Depending on the relative block length and different solvent compositions, these copolymers self-assemble into different supramolecular structures in toluene/dichloromethane (DCM) solution, including spherical micelles, bowl-shaped vesicles, multilayer vesicles, porous spheres, and large compound micelles. In methanol/DCM solution system, the crystalline PCL core disturbs the balance of free energy, thus results in a series of morphological changes including spherical micelles, worm-like rods, vesicles, coexisted vesicles and lamella, and finally platelet lamella.