Synthesis of an ABCD 4-Miktoarm Star Quaterpolymer Through a Diels-Alder Click Reaction

An ABCD 4-miktoarm star quaterpolymer with A = poly(ε-caprolactone) (PCL), B = poly(tert-butyl acrylate) (PtBA), C = polystyrene (PS) and D = poly(methyl methacrylate) (PMMA) arms was prepared using the Diels-Alder reaction strategy. Firstly, PCL with anthracene (PCL-Anth) and PtBA with furan-protected maleimide (PtBA-MI) end-functionalities were synthesized separately via ring-opening polymerization of ε-CL and atom transfer radical polymerization of tBA, respectively. These homo-polymers were linked via the Diels-Alder click reaction in toluene at 100°C in order to give PCL-b-PtBA co-polymer. Next, this block co-polymer is utilized successively as macroinitiator in nitroxide-mediated radical polymerization of styrene and in free radical photo-polymerization of MMA in order to achieve the PCL-PtBA-PS-PMMA 4-miktoarm star quaterpolymer.