PCL(5k)-PEG(2k)-NH2 is a monofunctional block copolymer with terminal amine. The polymer can react with a N-Hydroxysuccinimide (NHS) ester in physiological condition via amide bond formation. The self-assembling polymer can be used to prepare drug loaded nanoparticles where the drugs are encapsulated in the core of the micelles which then be delivered to a specific target. Reagent grade, for research purpose.