Atom Transfer Radical Polymerization (ATRP) and Ring-Opening Polymerization (ROP) were combined to synthesize diblock environmental friendly poly(E-caprolactone)-block-poly(methyl ether diethylene glycol methacrylate) (PCL-b-PMEO(2)MA) 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, E-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 alpha-bromide-omega-hydroxy bifunctional PCL macroinitiator. Secondly, the controlled ATRP of MEO(2)MA was tuned from the same bifunctional initiator. Finally, PCL-b-PMEO(2)MA were produced by carrying out ATRP of MEO(2)MA from PCL macroinitiator. Preliminary data on self-assembly of such thermo-sensitive PCL-b-PMEO(2)MA in aqueous phase are given.