Poly(ɛ-caprolactone)-block-polystyrene metallopolymers via sequential ROP and ATRP condition with in situ generated ruthenium catalyst

Poly(ɛ-caprolactone)-b-polystyrene with vacant bipyridine coordinating sites and metallated AB type diblock with well-defined metal loci in the polymer chain were synthesized and characterized. Solution atom transfer radical polymerization (ATRP) of styrene where a poly(ɛ-caprolactone) macromonomer acted as initiator and derivative complex of [Ru(p-cymene)Cl2]2 as catalyst is reported. ATRP reaction conditions with respect to polymer molecular weights and polydispersity indices (PDI) of the target bifunctional polymers were examined. Electronic absorption and emission spectra of the resultant functional polymers provided evidence of the ruthenium metal chromophores in the diblock copolymer. The thermal properties of all polymers were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), and indicated that they possess a high thermal stability and are miscible in the molten state. The semicrystalline nature of the PCL macroligand and the morphology of thin films of the metal free diblocks were also elucidated by combination of atomic force microscopy (AFM), scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD) studies.