PCL(2k)-PEG(2k)-NHS is an NHS activated & water insoluble block copolymer with polycaprolactone (PCL) hydrophobic block and PEG hydrophilic block. The coupling between NHS ester and amine forms a stable amide bond. In water, the polymer self-assembles to form micellar structure which can be used to encapsulate drugs. Reagent grade, for research purpose.