PCL(10k)-PEG(5k)-COOH allows self assembly when dispersed in water. The micelle structure consists of hydrophobic core polycaprolactone (PCL) and hydrophilic shell (PEG). It can be used to prepare drug nanocarrier in drug delivery system. The carboxylic acid (COOH) is reactive with amine in the presence of HATU or EDC to form a stable amide linkage. Reagent grade, for research purpose.