PCL(4k)-PEG(1k)-N3 is an amphiphilic block copolymer with terminal azide which can react with alkyne via CuAAC or SPAAC to form a stable triazole bond. In water, the polymer can form micelles which contains hydrophobic core (polycaprolactone (PCL)) and hydrophilic shell (PEG). It can be used to prepare drug nanocarrier in drug delivery system. Reagent grade, for research purpose.