PCL(5k)-PEG(2k)-N3 is a monofunctional block copolymer with hydrophobic (polycaprolactone (PCL)) block and hydrophilic PEG segment. The amphiphilic polymer has terminal azide which can undergo click reaction with alkyne molecule, such as DBCO/BCN or terminal alkyne (with Cu catalyst), via triazole bond formation. It can be used to prepare nanoparticles for drug delivery. Reagent grade, for research purpose.