PCL(5k)-PEG(1k)-N3 is click chemistry polymer. The azide can undergo azide-alkyne cycloaddition with cyclooctyne (Cu free) or terminal alkyne (with Cu catalyst) to form a stable triazole bond. The amphiphilic polymer can self assemble in water to form micelles with core and shell contains polycaprolactone (PCL) and PEG, respectively. It can be used to encapsulate hydrophobic drugs. Reagent grade, for research purpose.