PCL(3k)-PEG(5k)-N3 is a micelle-forming polymer for drug encapsulation in drug delivery system. The polymer has terminal azide which can react with alkyne molecule, such as DBCO/BCN, via copper free click chemistry. The polyster, polycaprolactone (PCL), is biodegradable via hydrolytic attack on the ester bonds. Reagent grade, for research purpose.