PCL(2k)-PEG(3k)-N3 is a micelle-forming polymer for drug encapsulation in drug delivery system. The polymer has terminal azide which can react with alkyne, such as cyclooctyne (DBCO/BCN) or terminal alkyne, to form a triazole bond. The polyster, polycaprolactone (PCL), is biodegradable via hydrolysis on the ester bonds. Reagent grade, for research purpose.