Thermo-sensitive and environmental friendly diblock copolymers obtained via ATRP/ROP combination

• Thermo-sensitive PCL-b-PMEO2MA has been obtained via ATRP/ROP strategy.
• Use of bismuth-based non toxic catalyst within ROP of ϵ-caprolactone.
• Thermo-responsive self-assembly that can load hydrophobic probes.

Atom Transfer Radical Polymerization (ATRP) and Ring-Opening Polymerization (ROP) were combined to synthesize diblock environmental friendly poly(ϵ-caprolactone)-block-poly(methyl ether diethylene glycol methacrylate) (PCL-b-PMEO2MA) through a sequential two-step strategy. These PCL-b-PMEO2MA copolymers were produced using 2-hydroxyethyl-2-bromoisobutyrate as bifunctional initiator. In the first step, ϵ-caprolactone was initiated by the hydroxyl group of this particular initiator. Tin octoate, zinc triflate and bismuth triflate were tested as non-toxic catalysts to obtain α-bromide–ω-hydroxy bifunctional PCL macroinitiator. Secondly, the controlled ATRP of MEO2MA was tuned from the same bifunctional initiator. Finally, PCL-b-PMEO2MA were produced by carrying out ATRP of MEO2MA from PCL macroinitiator. Preliminary data on self-assembly of such thermo-sensitive PCL-b-PMEO2MA in aqueous phase are given.