PCL(3k)-PEG(3k)-COOH is a carboxyl functionalized amphipathic polymer which can react with amino molecule in the presence of HATU or EDC to form a stable amide linkage. The polymer can self-assemble in water to form micelles where the core regions (polycaprolactone (PCL)) can be used to entrap/congregate hydrophobic drugs. Reagent grade, for research purpose.